OBD-II Code P0281: Cylinder 7 Contribution/Balance Fault

What Does P0281 Mean?

The Powertrain Control Module (PCM) detected cylinder #7 is underperforming. The PCM monitors crankshaft rotational speed after each cylinder fires; when it misses the expected acceleration from cylinder 7, it triggers this code to report the power imbalance.

Technical definition: The formal SAE/OBD-II definition is "Cylinder 7 Contribution/Balance Fault". It indicates the power contribution from cylinder 7 falls below a calibrated threshold compared to the engine's other cylinders.

Can I Drive With P0281?

⚠️Yes, But With Caution. You can drive short distances, but we strongly discourage it. Continued operation causes a rough ride, poor fuel economy, and severe damage. Unburnt fuel destroys the catalytic converter (a $1,000-$3,000+ repair), damages the Diesel Particulate Filter (DPF), or washes oil from the cylinder walls, causing internal engine failure. An injector stuck open causes the engine to hydrolock.

Common Causes

• Faulty, Dirty, or Clogged Fuel Injector (Very Common) — A stuck, clogged, or internally failed injector prevents the correct fuel volume from entering cylinder 7. This is the primary cause of P0281.
• Fuel Injector Circuit or Wiring Harness Fault (Common) — Loose connectors, corroded pins, or frayed wiring interrupt the PCM's signal to the injector. On engines like the Duramax L5P or Ford 6.0L, connector fretting and heat-degraded harnesses are notorious failure points.
• Ignition System Fault (Gasoline Engines) (Common) — A bad spark plug, weak ignition coil, or damaged plug wire on cylinder 7 prevents the fuel from igniting properly, resulting in a weak power stroke.
• Failed Active Fuel Management (AFM) Lifter (GM V8) (Less Common) — On GM V8 gasoline engines, the AFM system deactivates cylinders to save fuel. The specialized lifters collapse or stick, causing a complete loss of compression and triggering this code.
• Low Cylinder Compression (Less Common) — Mechanical failures like worn piston rings, a burnt valve, a leaking head gasket, or a worn camshaft lobe prevent cylinder 7 from building the pressure required to generate power.
• Fuel Delivery Issue (Less Common) — A weak fuel pump or clogged fuel filter causes low pressure across the engine, which sometimes manifests as a fault on a single, highly sensitive cylinder first.
• PCM Fault or Software Anomaly (Rare) — A software glitch or a burnt-out injector driver circuit inside the PCM incorrectly sets this code. Dealership software updates resolve the glitch, while a burnt driver requires PCM replacement.

Symptoms

• Check Engine Light On — The PCM illuminates the Malfunction Indicator Lamp (MIL). The light flashes if the misfire is severe enough to damage the catalytic converter.
• Rough Idle and Engine Vibration — The engine shakes or sputters, especially at stops or low speeds, because the dead cylinder throws off the engine's rotational balance.
• Hesitation and Loss of Power — The vehicle stumbles or feels sluggish during acceleration because it is operating on one less cylinder.
• Poor Fuel Economy — The engine works harder and dumps unburnt fuel to compensate for the weak cylinder, drastically reducing gas mileage.
• Fuel Smell from Exhaust — Raw fuel dumps into the exhaust system if the injector is stuck open or the cylinder fails to ignite the mixture.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Replace Fuel Injector for Cylinder 7 — Parts: $100 - $600, Labor: $200 - $800, ~2.5 hr book time (Intermediate)
• Replace Spark Plug and/or Ignition Coil — Parts: $20 - $100, Labor: $70 - $150, ~0.8 hr book time (DIY)
• Repair Fuel Injector Wiring or Connector — Parts: $10 - $60, Labor: $150 - $400, ~1.5 hr book time (Intermediate)
• Replace Failed AFM Lifters (GM V8) — Parts: $300 - $800, Labor: $1,500 - $3,000+, ~12 hr book time (Professional)
• Update or Reprogram Powertrain Control Module (PCM) — Parts: $0, Labor: $100 - $250, ~1.2 hr book time (Professional)

DIY vs Professional

• Replace Spark Plug and/or Ignition Coil 🟢 Beginner
  Tools: Basic socket set, spark plug socket, torque wrench.
• Repair Fuel Injector Wiring or Connector 🟢 Beginner
  Tools: Multimeter, wire strippers, crimpers, heat shrink, soldering iron.
• Replace Fuel Injector (Gasoline Port Injection) 🟢 Beginner
  Tools: Socket set, fuel line disconnect tool, torque wrench, safety glasses.
• Replace Fuel Injector (Diesel or GDI) 🟢 Beginner
  Tools: Specialized injector pullers, high-pressure line wrenches, bidirectional scan tool.
• Replace Failed AFM Lifters 🟢 Beginner
  Tools: Full engine tool set, valve spring compressor, camshaft holding tools.

Used vs. New Parts: Buying Guide

When a used part is worth it: A used part is acceptable for a standard port fuel injector on an older, high-mileage vehicle if the budget is tight. Never use a used high-pressure GDI or diesel injector.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Ensure the part number matches exactly.
• Purchase from a reputable salvage yard offering a warranty.
• Visually inspect for corrosion, cracks, or damaged electrical pins.

Decision logic:

• If The vehicle has low mileage (<80k) and uses a standard port injector → Buy a new OEM or high-quality aftermarket part for longevity.
• If The part is a high-pressure diesel or GDI injector → Buy new or professionally remanufactured parts due to high failure costs.
• If The vehicle is old (>150k miles) and the repair budget is very limited → A used injector with a 90-day warranty is an acceptable risk.

Warranty tradeoff: Used parts offer a 30-90 day parts-only warranty. New aftermarket parts offer 1-year to lifetime warranties. A used part warranty will not cover the labor to replace it if it fails.

Worst-case if a used part fails: $400 - $1200 if a used injector fails after installation, requiring repeat labor costs.

What Happens If You Wait — Timeline

1. 0-1 month: Code P0281 is set. Driver notices a slightly rough idle or minor hesitation, but no major drivability issues. (MPG impact: 3-8%% · Added cost: $20-75 in wasted fuel.)
2. 1-4 months: Engine vibration at idle becomes pronounced. Noticeable loss of power. Unburnt fuel intermittently overheats the catalytic converter. (MPG impact: 10-20%% · Added cost: $100-300 in wasted fuel.)
3. 4-8 months: Unburnt fuel melts the internal ceramic honeycomb of the catalytic converter. The Check Engine Light flashes during acceleration. (MPG impact: 20-30%% · Added cost: $1,000 - $3,500 (Catalytic converter replacement required).)
4. 8+ months / Severe Cases: A stuck-open injector washes lubricating oil off the cylinder walls, causing permanent scoring to the piston and rings. The engine may hydrolock. (MPG impact: 30-50%+% · Added cost: $3,000 - $8,000+ (Requires major engine repair or replacement).)

Cost of Not Fixing It

• 0-1 month: Noticeable drop in fuel economy (up to 15-25%), rough idle, and poor acceleration. (Added cost: Negligible, besides increased fuel cost.)
• 1-6 months: Unburnt fuel enters the exhaust, overheating and destroying the catalytic converter and oxygen sensors. (Added cost: $1,000 - $4,000)
• 6+ months: A stuck-open injector washes oil from cylinder walls, leading to piston ring damage and requiring engine replacement. (Added cost: $3,000 - $8,000+)

Diagnosis Steps

1. Read Codes & Analyze Live Data
   Use an OBD-II scanner to confirm P0281 and check for related codes (like P0307 or P0207). View live cylinder balance rates on diesel engines; a deviation greater than 10% on cylinder 7 confirms the fault.
   Tools: OBD-II Scanner with Live Data (Beginner)
2. Visual Inspection of Cylinder 7
   Locate cylinder 7 using a service manual. Inspect the fuel injector, ignition coil, wiring, and connectors for obvious damage, corrosion, or fuel leaks.
   Tools: Flashlight, Service Manual (Beginner)
3. Swap Ignition Components (Gasoline Engines)
   Swap the ignition coil and spark plug from cylinder 7 to an adjacent cylinder (e.g., cylinder 5). Clear codes and drive. If the code changes to P0275 (Cylinder 5), the ignition coil or plug is faulty.
   Tools: Socket Set, Spark Plug Socket (Intermediate)
4. Swap Fuel Injectors
   If the ignition swap fails, swap the fuel injector from cylinder 7 to another cylinder. Clear codes and run the engine. If the code follows the injector, replace the faulty injector.
   Tools: Socket Set, Pliers, Fuel Line Disconnect Tool (Advanced)
5. Test Injector Resistance and Circuit
   Disconnect the injector. Use a multimeter to verify resistance across the injector pins (typically 10-19 ohms for port injection). Next, plug a noid light into the harness connector and crank the engine; a rapid flash confirms the PCM is sending the firing signal.
   Tools: Multimeter, Noid Light Set (Advanced)
6. Perform a Compression Test
   If fuel and ignition systems function properly, test cylinder 7's compression. A reading 15-20% lower than other cylinders indicates a mechanical failure like worn rings, a bad valve, or a collapsed AFM lifter.
   Tools: Compression Tester Gauge (Advanced)
7. Advanced: Analyze Diesel Cylinder Balance Rates
   On diesels, monitor balance rates at warm idle in Park. A strong positive reading (+4.0 mm³/sec) means the ECM is adding fuel to compensate for low compression. A strong negative reading (-4.0 mm³/sec) means the injector is leaking or over-fueling.
   Tools: Advanced OBD-II Scanner (Advanced)
8. Advanced: Check Fuel System Pressures
   Verify low-pressure lift pump specs and high-pressure common rail actual vs. desired pressures. Significant deviations indicate a weak pump or a massive injector leak.
   Tools: Advanced OBD-II Scanner, Fuel Pressure Gauge (Advanced)
9. Advanced: Test Ford 6.0L FICM Voltage
   For Ford 6.0L PowerStrokes, test the Fuel Injection Control Module (FICM) output voltage during a cold crank and while running. It must remain at or above 45V; anything lower indicates a failing power supply.
   Tools: Multimeter or Advanced Scanner (Advanced)
10. Check for TSBs and Software Updates
    Check manufacturer Technical Service Bulletins (TSBs) for your specific VIN. A PCM software update performed by a dealership is sometimes the only required fix.
    Tools: Online Repair Database (Professional)

When This Code Triggers (Freeze-Frame Conditions)

• Engine Coolant Temp: 180-210°F (82-99°C) (Fully warmed up)
• Engine RPM: 1500-2500 RPM (Steady cruise or light acceleration)
• Engine Load: 30-60% (Moderate load, not at idle or full throttle)
• Vehicle Speed: 45-65 mph (Highway or steady-state driving)

Related Codes

• P0307 — Means "Cylinder 7 Misfire Detected." P0281 explains *why* the misfire is happening (lack of power). Having both points to fuel or compression issues.
• P0207 — Means "Injector Circuit/Open - Cylinder 7." Seeing this with P0281 guarantees an electrical problem in the injector's wiring, connector, or internal coil.
• P0200 — A general "Injector Circuit Malfunction." If seen with P0281, it points to a systemic problem like a faulty injector driver module (FICM) or main wiring harness.
• P0263, P0266, P0269, etc. — Contribution codes for other cylinders. Multiple codes indicate a wider problem like low fuel pressure, contaminated fuel, or a failing PCM.

Climate & Environmental Factors

• Cold Weather: Cold temperatures exacerbate P0281 issues. On Ford 6.0L diesels, low battery voltage during cold starts strains the FICM, accelerating failure. Diesel fuel also gels below 20°F (-6°C), starving injectors.
• Humidity: High humidity promotes corrosion on electrical connectors, leading to intermittent open or short circuits in the injector harness.
• High Altitude: Lower air density affects the air-fuel mixture. While the PCM compensates, it makes underlying injector or compression issues more apparent.

How to Talk to a Mechanic About This Code

Say this: "I have a Check Engine Light on and my scanner shows code P0281, a cylinder 7 contribution fault. I'd like to schedule a diagnostic appointment. Can you please check the cylinder balance rates on your scan tool and inspect the fuel injector, its wiring, and connector for cylinder 7? If it's a gasoline engine, I'd also like the spark plug and coil checked."

This signals to the shop that you understand the code is specific. It directs them to the most likely causes (fuel, electrical, ignition) and requests specific data (balance rates) that confirms the problem, preventing unnecessary diagnostics.

Avoid saying:

• 'My check engine light is on, can you just fix it?'
• 'My car is running rough, I think it needs a tune-up.'
• 'Just do whatever you think is necessary.'

Questions to ask before authorizing the repair:

• What were the cylinder balance rates for cylinder 7 compared to the others?
• Did you perform a compression test on cylinder 7, and what was the result?
• If the injector is the problem, did you test the wiring and connector to confirm they are good?
• If you are replacing the injector, does the new one need to be coded to the computer, and is that included in the price?
• What is the warranty on the parts and labor for this repair?

Where to Take It: Dealer vs Independent vs Chain

• Dealer: Recommended for complex, warranty, or manufacturer-specific mechanical failures. For a standard injector or wiring issue on an out-of-warranty vehicle, an independent shop is more cost-effective.
  Best for: Vehicles under powertrain warranty., Known manufacturer-specific issues like GM AFM lifter failure or complex BMW injector problems., Repairs requiring a PCM software update.
  Downsides: Highest labor rates, often 1.5-2x more than independent shops., May recommend replacing an entire set of injectors when only one is bad. (Typical cost: +50% vs. baseline)
• Independent Shop: Best fit for most P0281 scenarios, especially for out-of-warranty gasoline engines and common diesel injector swaps. Seek out a shop with specific experience in your vehicle's brand.
  Best for: Out-of-warranty vehicles where cost is a major factor., Common P0281 causes like a single bad injector, spark plug, or wiring issue., Shops specializing in diesel repair (for PowerStroke, Duramax, Cummins).
  Downsides: Quality and diagnostic capabilities vary widely; look for ASE certifications., May not have access to the very latest manufacturer software updates. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID for initial diagnosis. The causes of P0281 are often too complex for a typical chain shop, leading to unnecessary parts replacement.
  Best for: Simple, clear-cut ignition problems (spark plug/coil replacement) if you've already diagnosed it yourself.
  Downsides: Technician skill varies greatly; lacks advanced diagnostic tools for complex fuel systems., High pressure to upsell services; high risk of misdiagnosis. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost exceeds 50% of the car's private-party value, seriously consider selling or trading it in rather than repairing it.

• Car worth $15000, fix is $2500: Fix it. The repair cost is well below the 50% threshold and restores the vehicle's primary function.
• Car worth $8000, fix is $3500: Borderline. This is a major repair (like GM AFM lifters). Get a second opinion and evaluate the car's overall condition before proceeding.
• Car worth $4000, fix is $2800: Walk away. The repair cost is over 50% of the vehicle's value. It is not financially sensible to proceed with the repair.

What Scan Tool You Need for This Code

Minimum: A scanner that reads live engine data, specifically cylinder balance rates (for diesels) or monitors engine RPM changes during a manual cylinder cutout test.

A basic $20 code reader only shows the P0281 code. It cannot show the live data needed to confirm which cylinder is weak and by how much, making diagnosis a guessing game.

Budget: BlueDriver Pro (~$100) — Connects to your smartphone and displays live data, including engine RPM and misfire counts. It provides freeze-frame data and generates repair reports.

Mid-range: Foxwell NT510 Elite / Autel MaxiCheck MX808S (~$180-350) — Offers bidirectional control to perform a 'power balance test' by shutting off individual injectors to see the RPM drop. Performs injector coding required on modern diesels.

Professional: Autel MaxiSys MS906Pro / XTOOL D7 (~$500-1200) — Provides full OEM-level diagnostics, advanced bidirectional controls, comprehensive live data graphing, and performs all programming functions for complex diesel systems.

Rent vs buy: Auto parts stores read codes for free, but their basic readers won't show live data for P0281. Buying a budget or midrange scanner is a worthwhile investment for DIY diagnosis.

How to Clear the Code After You Fix It

1. Use an OBD-II scan tool to clear the fault codes
2. Perform a complete OBD-II drive cycle to allow readiness monitors to run
3. Rescan the vehicle to ensure no codes have returned

Drive cycle (~20 minutes): Cold start (engine temp below 122°F). Idle for 2-3 minutes with electrical load. Accelerate to 55 mph and hold steady for 3-5 minutes. Coast down to 20 mph without braking. Accelerate again to 55-60 mph and hold for 5 minutes. Coast down again.

Readiness monitors affected: Catalyst Monitor, Oxygen Sensor (O2S) Monitor, Misfire Monitor, Fuel System Monitor

Before emissions retest: drive at least 100 miles to fully set monitors.

Watch out for:

• Disconnecting the battery clears the code but resets all readiness monitors, causing an automatic emissions failure.
• The code returns immediately if the underlying mechanical or electrical fault is not repaired.
• Failing to let the vehicle cool down completely (8+ hours) prevents certain monitors from running.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An active Check Engine Light for P0281 is an automatic smog check failure. All readiness monitors must be 'Ready' for the test to proceed.
• New York: A vehicle automatically fails the NYS inspection if the Check Engine Light is on. Clearing the code right before the test results in a failure due to 'Not Ready' monitors.
• Texas: In counties requiring emissions testing, an illuminated Check Engine Light from a P0281 code causes an automatic failure of the OBDII test.

Most Commonly Affected Vehicles

• Ford F-250/F-350 Super Duty (2003-2019) — Extremely common on 6.0L PowerStroke engines due to FICM failure or injector harness issues. Also frequent on 6.7L PowerStrokes as a failing injector.
• Chevrolet / GMC Silverado / Sierra 2500HD/3500HD (2001-2019) — Early LB7 Duramax engines (2001-2004) suffer high injector failure rates. On L5P Duramax engines (2017-2019), injector connector fretting is the primary cause.
• Dodge / Ram Ram 2500/3500 (2007-2024) — On 6.7L Cummins diesels, this code points directly to a failing injector or wiring harness chafing near the engine block.
• Chevrolet / GMC Silverado / Sierra 1500 (and V8 SUVs) (2007-2019) — On gasoline V8 engines (5.3L, 6.2L) with Active Fuel Management (AFM), this code is frequently caused by a collapsed AFM lifter.
• BMW Various with N63 V8 engines (e.g., 550i, 650i, 750i, X5) (2008-2016) — Early N63 V8 engines suffer from failing piezoelectric fuel injectors. It is standard practice to replace all injectors on the affected bank simultaneously.
• Nissan / Infiniti Titan, Armada / QX56, QX80 (2004-2021) — On the 5.6L V8 engine, this code points to a faulty injector, ignition coil, or related wiring.
• Toyota Tundra, Sequoia (2007-2021) — For the 5.7L V8, this code appears due to a failed fuel injector or issues with the secondary air injection system.
• Ford E-Series Van (2005-2014) — V10 gasoline engines develop this code due to a failing injector or bad ignition coil. Engine access is difficult, increasing labor costs.

Manufacturer-Specific Notes

• Ford: On 6.0L PowerStrokes, low voltage from a failing Fuel Injection Control Module (FICM) causes contribution codes. Always test FICM voltage; it must remain above 45 volts.
• General Motors (GM) - Diesel: On L5P Duramax diesels, injector connector pin fretting causes P0281. TSB 17-NA-171 also notes a software anomaly requiring an ECM update.
• General Motors (GM) - Gasoline: On V8s with Active Fuel Management (AFM), a failed lifter is a common mechanical cause. The lifter sticks, resulting in zero compression for that cylinder.
• BMW: On N63 V8 engines, factory piezoelectric fuel injectors have a high failure rate. It is standard practice to replace all four injectors on the affected bank simultaneously.

Real Owner Stories

2015 Silverado 5.3L with 135K miles - The Dreaded AFM Lifter Failure

The truck developed a bad chirp and an intermittent misfire on cylinder 5, eventually setting a contribution code.

What they tried:

1. Replaced all lifters after one collapsed.
2. Switched to high-quality synthetic oil and a friction-reducing additive with every oil change.

Outcome: The engine chirp disappeared, performance returned, and the issue has not recurred.

Lesson: On GM V8s with AFM, a contribution code accompanied by a chirp or tick is a failing lifter. Proactive measures like frequent high-quality oil changes extend lifter life.

2012 Ford F-250 6.7L PowerStroke - The Misleading Injector Code

The owner replaced the cylinder 6 injector for a P0278 code. Two days later, a P0281 (Cylinder 7) code appeared.

What they tried:

1. Cleared the codes and reset the fuel trim adaptations using a scan tool.

Outcome: The P0281 code did not return. The PCM's learned fuel adjustments from the previous bad injector caused it to incorrectly flag cylinder 7.

Lesson: After replacing a diesel fuel injector, you must program the new injector's IQA code and reset the PCM's fuel trim adaptations to prevent false codes.

Ford 6.0L PowerStroke - Chasing a P0281 After Major Work

Immediately after installing head studs, the engine threw a P0281 code with a rough idle and a 'thump'.

What they tried:

1. Checked FICM voltage (tested good).
2. Pulled the passenger side valve cover for a visual inspection.

Outcome: Two valve bridge pieces had fallen off and one rocker arm was broken. The code was caused by a mechanical assembly error, not a bad injector.

Lesson: If P0281 appears immediately after major engine repair, suspect an installation error before buying new parts.

How to Prevent This Code From Triggering

• Use High-Quality Fuel from Top-Tier Stations (Every fill-up) — Quality fuel contains detergents that prevent carbon deposits and varnish on injector pintles, maintaining a proper spray pattern.
• Perform Regular Fuel System Cleaning (Every 5,000-10,000 miles) — Bottled fuel system cleaners dissolve minor carbon deposits before they become major clogs.
• Change Fuel Filters on Schedule (Per manufacturer schedule (e.g., 15,000-30,000 miles)) — Clean filters ensure injectors receive uncontaminated fuel, preventing abrasive wear and internal corrosion.
• For GM V8s with AFM: Shorten Oil Change Intervals (Every 3,000-5,000 miles) — AFM lifters are highly sensitive to oil cleanliness. Frequent full synthetic oil changes prevent sludge that causes lifters to stick.
• For Ford HEUI Diesels: Use a Quality Oil Additive (With every oil change) — Additives like Archoil AR9100 reduce friction and clean deposits, preventing cold-start misfires caused by injector stiction.

Frequently Asked Questions

What's the difference between a 'contribution' code and a 'misfire' code?

A misfire code (P0307) means the PCM detected a generic hiccup in the engine's rhythm. A contribution code (P0281) means the computer precisely measured the crankshaft's speed and confirmed cylinder 7 is physically weaker than the rest.

Can I just use a fuel injector cleaner from a bottle to fix this?

While fuel system cleaner is good maintenance, it rarely fixes an active P0281 code. The issue is usually a completely failed injector, an electrical fault, or a mechanical problem that additives cannot repair.

Why did the code come back after I replaced the injector?

The code returns if the real issue is a faulty electrical connector, low cylinder compression, or a bad PCM driver. On modern diesels, failing to program the new injector's flow rate code into the PCM also causes the code to return.

What happens if I keep driving with a cylinder imbalance?

Continued driving is highly destructive. Unburnt fuel overheats and melts the catalytic converter, resulting in a $1,000-$3,000 repair. A stuck-open injector also washes lubricating oil off cylinder walls, causing permanent engine scoring or hydrolock.

Why is this code so common on diesel trucks?

Diesel fuel systems operate at extreme pressures, often exceeding 30,000 PSI. The injectors are highly complex precision parts subjected to immense stress, making them more susceptible to wear and electronic failure than gasoline injectors.

My mechanic wants to replace all 8 injectors. Is that necessary?

On high-mileage vehicles, if one injector fails, the others are likely near the end of their lifespan. Replacing them all saves significant future labor costs, especially if they are difficult to access. For a low-mileage failure, replacing only the faulty one is reasonable.

What is a common misdiagnosis for P0281?

A common mistake is replacing the spark plug and coil when the code is P0281 but not P0307; contribution faults are usually fuel or mechanical issues. Another error is replacing the PCM before thoroughly testing the injector wiring.

Key Takeaways

• Code P0281 indicates cylinder #7 is underperforming, causing an immediate 10-20% drop in fuel economy and a noticeably rough idle.
• A faulty, clogged, or stuck fuel injector on cylinder 7 causes over 60% of P0281 codes, making it the primary diagnostic target.
• Diagnose gasoline engines by swapping the cylinder 7 ignition coil and spark plug to an adjacent cylinder to quickly rule out a $50 ignition failure.
• Stop driving the vehicle immediately; a stuck-open injector dumps raw fuel into the exhaust, destroying a $2,000 catalytic converter in under 50 miles.