P0507 on 2003-2007 Infiniti G35: High Idle Causes and Fixes

What's Unique About the 2003-2007 Infiniti G35

The G35 platform is famously sensitive to any changes in the air intake system. Simply cleaning the throttle body or disconnecting the battery can erase the Engine Control Module's (ECM) memory for the correct idle position, immediately causing a high idle and the P0507 code. The required 'Idle Air Volume Learning' procedure, often called the 'pedal dance', is notoriously difficult to perform correctly without a dealer scan tool, leading to significant owner frustration. Forum users report trying the procedure up to 50 times before getting it right. Furthermore, the 2007 model year is a split-generation, with the sedan featuring a newer VQ35HR engine with dual throttle bodies, while the coupe retained the older VQ35DE with a single throttle body, complicating diagnosis and parts selection.

Generation note: Yes, this range covers two different engine configurations. The 2003-2006 G35 (all models) and the 2007 G35 Coupe use the VQ35DE engine with a single electronic throttle body. The 2007 G35 Sedan uses the updated VQ35HR engine, which is easily identified by its dual air intakes and dual electronic throttle bodies. This means the 2007 sedan has two throttle bodies that can get dirty, two gaskets that can leak, and two potential points of electronic failure.

Symptoms You May Notice

• Check Engine Light is on
• Engine idling higher than normal (e.g., 800-1200 RPM instead of the usual ~650 RPM).
• Rough or surging idle, sometimes fluctuating between 1,200 and 2,000 RPM.
• Increased fuel consumption
• With an automatic transmission, the car may feel like it's pushing forward or lurching at a stop.

Most Likely Causes

1. Idle Air Volume Learning (IAVL) Procedure Required 🔴 High Probability The ECM's learned idle values are volatile and easily lost after cleaning the throttle body, disconnecting the battery, or replacing related components. This is the most common reason for a P0507 code after maintenance.
   How to confirm: If the code appeared immediately after you cleaned the throttle body or disconnected the car battery, this is almost certainly the cause.
   Typical fix: Perform the three-part relearn procedure: 1. Accelerator Pedal Released Position Learning, 2. Throttle Valve Closed Position Learning, and 3. Idle Air Volume Learning. The manual 'pedal dance' is very timing-sensitive and may take multiple attempts. A professional scan tool like the Nissan Consult can perform the relearn instantly. All electrical loads (A/C, radio, lights, defroster) must be off and the steering wheel must be straight.
   Est. part cost: $0
2. Dirty Electronic Throttle Body 🔴 High Probability → Shop Fuel Injection Throttle Body Carbon and oil vapor from the PCV system build up around the throttle plate, preventing it from closing completely. This small gap allows uncommanded air to enter, raising the idle.
   How to confirm: Visually inspect the inside of the throttle body and the edges of the throttle plate for black, sticky carbon buildup. The engine side is often dirtier than the intake side.
   Typical fix: Carefully clean the throttle body bore and plate with a dedicated throttle body cleaner and a soft, lint-free cloth. Do NOT move the plate by hand on a powered-up car, as this can damage the delicate internal gears. After cleaning, the IAVL procedure is mandatory. 🎬 Watch: How to clean your throttle body and perform the relearn.
   Est. part cost: $5-$15 for cleaner
3. Vacuum Leak 🟡 Medium Probability Over time, rubber hoses and plastic intake components can become brittle and crack from engine heat and age.
   How to confirm: Listen for a hissing or whistling sound near the top of the engine at idle. A common failure point is the plastic air intake tube between the air filter and throttle body, which can crack on the underside. Another method is to spray brake cleaner or a propane torch (unlit) around vacuum lines and gaskets; a change in idle RPM indicates the location of the leak. For less obvious leaks, a smoke test is the most effective diagnostic method. A healthy VQ35DE should pull a steady 20-21 inHg of vacuum at idle.
   Typical fix: Replace the cracked hose or failed gasket. The intake manifold plenum gasket is a common culprit, as are small vacuum tees and the PCV hose.
   Est. part cost: $10-$100 depending on the hose or gasket
4. Faulty PCV Valve ⚪ Low Probability → Shop PCV Valve The PCV valve can get stuck open, creating a constant vacuum leak. It's an often-neglected, inexpensive maintenance item that contributes to oil consumption and intake carbon buildup. 🎬 See how a new PCV valve fixes oil consumption and idle issues.
   How to confirm: Remove the valve (located on the passenger side valve cover on the VQ35DE) and shake it. If it doesn't rattle freely, it's stuck and should be replaced. Given its low cost, it's often replaced as a preventative measure during diagnosis.
   Typical fix: Replace the PCV valve. This requires a deep 23mm or 24mm socket. 🎬 Watch this 5-minute DIY guide to replacing your PCV valve. Be careful not to overtighten the new valve into the plastic valve cover. Replace its hose if it's brittle or swollen.
   Est. part cost: $20-$35 for the valve.

Rare But Worth Checking

• Faulty Electronic Throttle Body: → Shop Fuel Injection Throttle Body If cleaning the throttle body and performing the relearn procedure repeatedly fails, and no vacuum leaks are found, the throttle body's internal motor or position sensor may have failed. This is especially true if you manually forced the throttle plate open while cleaning it, which can damage the internal gears. This may also be accompanied by other throttle-related codes like P1121.
• Leaking Valve Cover Gasket: → Shop Engine Valve Cover On the VQ35DE, the spark plug tube seals are integrated into the valve cover. When they fail, oil leaks into the spark plug wells. This can cause a misfire, but it can also create a vacuum leak through the cover itself, contributing to a high idle.

Diagnosis Steps

1. Scan for any other codes. Address any throttle position sensor (TPS), accelerator pedal position (APP) sensor, or misfire codes first.
2. If maintenance was just performed (throttle cleaning, battery disconnect), immediately attempt the full Idle Air Volume Learning procedure. Ensure all prerequisites are met: engine fully warmed up, all accessories and lights off, steering wheel straight, and transmission in Park/Neutral.
3. Visually inspect the air intake ducting between the air filter box and the throttle body for any cracks or loose clamps. The ribbed section is a common failure point.
4. Inspect and clean the electronic throttle body with appropriate cleaner. Do not use a wire brush or force the throttle plate. After cleaning, repeat the Idle Air Volume Learning procedure. This may take several tries.
5. If the idle is still high, inspect the PCV valve and hose. The valve is on the passenger-side valve cover. Shake the valve to ensure it rattles; if not, replace it.
6. If the problem persists, perform a smoke test to find hidden vacuum leaks, paying close attention to the intake manifold plenum gasket and all small vacuum hoses connected to the plenum.
7. If no vacuum leaks are found and the relearn procedure will not 'stick' (i.e., the idle reverts to high after a restart), the issue may be a faulty throttle body.
8. As a last resort, an ECM software update from an Infiniti dealer may be required, as suggested in TSB ITB05-042 for related issues.

Parts You'll Likely Need

• PCV Valve (OEM #11810-6N202) — A stuck PCV valve is a common cause of a vacuum leak that leads to a high idle. It is an inexpensive and simple part to replace during diagnosis.
  Trusted brands: Nissan OEM, Standard Motor Products, Duralast
  OEM price range: $20-$30
  Aftermarket price range: $10-$20
• Electronic Throttle Body (VQ35DE) (OEM #16119-8J10C (supersedes 16119-8J103, 16119-8J10A, 16119-8J10B)) — While often just dirty, the throttle body can fail electronically. This is a last resort after cleaning, relearning, and checking for vacuum leaks have failed. This single throttle body fits 2003-2006 G35 and 2007 G35 Coupe.
  Trusted brands: Hitachi (OEM Manufacturer), Bosch, Dorman
  OEM price range: $200-$400
  Aftermarket price range: $120-$250
• Electronic Throttle Body (VQ35HR) (OEM #16119-JK20D (or 16119-JK20A/B)) — The 2007 G35 Sedan uses the VQ35HR engine with two throttle bodies (left and right are the same part). Failure is less common than on the DE, but they can still fail.
  Trusted brands: Hitachi (OEM Manufacturer), Nissan Value Advantage (NVA)
  OEM price range: $200-$350 per side
  Aftermarket price range: $150-$250 per side
• Intake Manifold Plenum Gasket (OEM #14032-AM600) — This gasket can fail over time, creating a significant vacuum leak that is hard to spot without a smoke test. It's a common leak point when P0507 is present and the throttle body isn't the cause.
  Trusted brands: Nissan OEM, Fel-Pro
  OEM price range: $20-$40
  Aftermarket price range: $10-$25

Technical Service Bulletins (TSBs) & Recalls

• ITB05-042: A TSB for 2002-2005 Nissan/Infiniti vehicles that addresses high idle and related codes. It suggests that if the Idle Air Volume Learning procedure does not resolve the issue, an ECU software update (reprogram) may be necessary.

Platform-Specific Known Issues

• The manual Idle Air Volume Learning procedure is notoriously difficult and timing-sensitive, often requiring multiple attempts to succeed. Forum users describe it as a 'crap shoot' and have reported trying over 50 times.
• The 2007 G35 Sedan uses the VQ35HR engine with dual throttle bodies, doubling the potential failure points compared to the single-throttle VQ35DE engine in earlier models and the 2007 coupe.
• A Technical Service Bulletin (TSB ITB05-042) was issued for this common high-idle issue on 2002-2005 Nissan/Infiniti vehicles, suggesting an ECU software update may be needed if the relearn procedure fails repeatedly.
• Some owners on forums have resorted to unconventional methods to force the idle down before performing the relearn, such as temporarily unplugging a fuel injector to get the RPMs into the target range for the procedure to 'take'. This is not a recommended practice.

Diagnostic Flowchart

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0506 — This is the companion code for 'Idle Air Control System RPM Lower Than Expected.' It can be caused by the same set of issues, such as a severely dirty throttle body preventing the plate from opening properly or a failed relearn procedure.
• P0171 — System Too Lean (Bank 1). A significant vacuum leak, a primary cause of P0507, allows unmetered air into the engine. This not only raises the idle speed but also creates a lean air-fuel mixture, triggering P0171.
• P0174 — System Too Lean (Bank 2). Similar to P0171, this code is often set alongside P0507 when a large vacuum leak (e.g., intake plenum gasket) affects both cylinder banks.
• P0300 — Random/Multiple Cylinder Misfire Detected. A vacuum leak large enough to trigger P0507 can lean out the air-fuel mixture to the point of causing misfires across multiple cylinders.
• P0123 — Throttle/Pedal Position Sensor 'A' Circuit High. Diagnostic procedures state that any throttle position sensor (TPS) codes must be addressed before P0507, as a faulty TPS provides incorrect data to the ECM, making proper idle control impossible.
• P2135 — Throttle/Pedal Position Sensor/Switch 'A'/'B' Voltage Correlation. Like other TPS/APP codes, this indicates a problem with the sensors that command the throttle. The ECM cannot reliably control idle if it receives conflicting data, so this code must be fixed first.

Frequently Asked Questions