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Engine Intake Air Temperature Sensor for 1994-1999 GMC K1500 Trucks

Is your GMC K1500 running rough or getting bad gas mileage? A faulty intake air temperature sensor could be the culprit.

3 minutes to read 1994-1999 GMC K1500
Difficulty
1/5
Est. Time
0.25 hrs
DIY Doable?
✅ Yes
Shop Labor
$25-$50
⚠️ Drivable, but... — Yes, you can drive, but you will experience poor fuel economy and rough engine performance until it is replaced.
Key Takeaways
  • A bad IAT sensor commonly causes a Check Engine Light, poor gas mileage, and rough running on a K1500.
  • Replacement is extremely easy and often requires no tools, making it a great DIY job.
  • For this part, quality aftermarket brands like Standard Ignition provide reliable performance at a lower cost than OEM.
  • Common fault codes associated with this part are P0112 and P0113.
The Engine Intake Air Temperature (IAT) sensor on your 1994-1999 GMC K1500 is a small but critical part of the engine management system. It measures the temperature of the air going into your engine. The engine's computer, or ECU, uses this information to figure out how dense the air is. Colder air is denser than warm air, so the computer adjusts the amount of fuel injected and modifies the ignition timing to match. This ensures your engine runs efficiently, giving you the best possible power and fuel economy.

Is Your K1500's IAT Sensor Failing?

A bad Intake Air Temperature (IAT) sensor can cause problems that seem bigger than they are. Because the sensor sends bad information to the engine's computer, the air-fuel mixture can be too rich (too much fuel) or too lean (not enough fuel). This can lead to several noticeable issues.

🎬 Watch this video to see common bad IAT sensor symptoms.

Common symptoms include a Check Engine Light, poor fuel economy, rough idling, and hesitation when you press the gas pedal. In some cases, your truck might be hard to start, especially in cold weather. You might also notice the engine seems to surge or misfire.

Choosing a New Aftermarket IAT Sensor

For a 1994-1999 GMC K1500, you don't necessarily need to buy an expensive OEM part from the dealer. High-quality aftermarket sensors from reputable brands offer a great balance of performance and value. This is a simple sensor, and trusted aftermarket companies have perfected the design.

Brand Quality Comparison

Brand Our Assessment
Standard Ignition (SMP) Standard is a well-respected brand known for making reliable, professional-grade parts that meet or exceed OE specifications. They are a trusted choice for a durable replacement.
True Tech True Tech is often associated with automotive repair shops that are part of networks like NAPA Auto Care. Reviews for shops using these parts are generally positive, indicating they are a reliable and cost-effective option for this type of repair.
ACDelco (OEM) This is the original equipment manufacturer for GM vehicles. While it guarantees a perfect fit and function, it is typically the most expensive option. For a simple sensor on an older truck, a quality aftermarket part is often a more practical choice.

Known Issues for This Generation K1500

There are no specific recalls or widespread Technical Service Bulletins (TSBs) from GMC for the IAT sensor on the 1994-1999 K1500. Failures are typically due to age, heat exposure, or contamination from oil or dirt. Sometimes, the wiring or connector can become damaged or corroded, causing a bad signal.

Pro Tip: Check the Location First

On these trucks, the IAT sensor is usually located in the plastic air intake tube, between the air filter box and the throttle body. It's a simple push-in sensor with an electrical connector. Confirming its location before you buy will ensure you get the right part and understand the simple replacement process.

Frequently Asked Questions (FAQ)

Where is the IAT sensor on my 1994-1999 K1500?

The sensor is almost always found in the hard plastic elbow or tube coming from the air filter box, right before the Mass Airflow (MAF) sensor. It is held in by a rubber grommet and has a two-wire connector.

Is this part hard to replace by myself?

No, this is one of the easiest sensors to replace. No tools are required for the repair on many of these trucks. You simply disconnect the electrical plug, wiggle the old sensor out of the intake tube, and pop the new one in.

🎬 See a step-by-step guide for replacing the sensor yourself.
What happens if I don't replace a bad IAT sensor?

You will continue to experience poor engine performance, bad gas mileage, and a rough idle. 🎬 Learn how a faulty sensor impacts your fuel economy. Over time, running with a very rich or lean fuel mixture could potentially lead to other issues like carbon buildup or damage to the catalytic converter.

Are the cheap aftermarket sensors on eBay or Amazon good enough?

While tempting, it's best to stick with known brands like Standard Ignition or True Tech. These brands have quality control processes to ensure the sensor's thermistor is accurate. An inaccurate sensor, even a new one, will cause the same performance problems you're trying to fix.

Symptoms Of A Bad IAT Sensor (Intake Air Temperature Sensor)
Symptoms Of A Bad IAT Sensor (Intake Air Temperature Sensor)
Signs of a Faulty intake air temperature (IAT) sensor
Signs of a Faulty intake air temperature (IAT) sensor
Symptoms Of Bad Intake Air Temperature Sensor - Easy Car Electrics
Symptoms Of Bad Intake Air Temperature Sensor - Easy Car Electrics
Dirty or Bad IAT Sensor Symptoms: The Main Reason Your Gas Mileage Sucks.
Dirty or Bad IAT Sensor Symptoms: The Main Reason Your Gas Mileage Sucks.
How to Replace IAT Sensor 88-98 GMC K1500 5.7L V8 Sierra
How to Replace IAT Sensor 88-98 GMC K1500 5.7L V8 Sierra

Technical Specifications

OEM Part Numbers: 25037334 12160244

This is a 2-terminal thermistor sensor that modifies a 5-volt reference signal from the ECU based on air temperature. It typically has a 3/8" - 18 NPTF thread or is a push-in style for the air intake tube.

Wrenchy
Article researched & written by
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Meet Wrenchy → Updated Apr 19, 2026

The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.

Year Coverage
This article covers the Engine Intake Manifold Temperature Sensor for:
  • GMC K1500: 199419951996199719981999
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