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1998 Grand Am 2.4L DOHC Stalls at Idle with P0113 Code - Intake Air Temp Sensor Circuit High Input

Model: 98 Grand Am Fault Code: P0113 Posted: 2012-09-01 09:03

Hi everyone, I'm new to car diagnostics and I have a 1998 Grand Am 2.4L DOHC engine. When I start the car, it may run smoothly at idle for about 30 seconds before stalling completely. If I give it gas while idling, it immediately stalls. After several hours of troubleshooting, the SES light turned on. The scanner shows the following diagnostic trouble code: - P0113: Intake Air Temperature (IAT) Sensor Circuit High Input - Fuel System 1: Active - Fuel System 2: Not applicable - Calculated Load Percentage: 19.2% - ECT (Engine Coolant Temp): 136°F - STFT B1 (%): 6.5 - LTFT B1 (%): 13.2 - MAP (Manifold Absolute Pressure): 9.1 inHg - RPM: 893 The engine behavior—stalling at idle and failing when given throttle—is concerning, especially with the P0113 code. I'm looking for clear guidance on how to diagnose and fix this issue. Any advice or suggestions would be greatly appreciated. Thank you in advance.

Related fault codes
P0113
Comments (2)
Anonymous 2012-09-01 09:47

Check the freeze frame data from your scanner—what is the voltage and temperature reading reported by the IAT sensor? \n\nSince the vehicle isn't running, start with basic diagnostics: verify fuel pressure using a gauge, check spark at multiple plugs, and test for injector pulsing. \n\nA potential guess: low MAP readings (like 9.1 inHg) may indicate vacuum leaks. Inspect all hoses and connections near the intake manifold to rule out this possibility.

Anonymous 2014-01-06 12:39

Hi, late reply but wanted to share some insights on this P0113 issue. \n\nWith a MAP reading of just 9.1 inHg, it's not uncommon for the engine to exhibit erratic idle behavior and sudden stalling—this suggests poor vacuum control or intake pressure issues. \n\nThe P0113 code specifically points to hot exhaust gases entering the intake manifold, which can override normal vacuum conditions and cause the engine to stall. \n\nHow do hot exhaust gases get into the intake? Likely due to a major restriction in the exhaust system—such as a clogged catalytic converter or a blocked silencer baffle at a sharp bend. \n\nTo test this: measure exhaust back pressure, or simply listen for a hissing sound when the engine stalls. \n\nTry removing the exhaust system just after the manifold (before the catalytic converter), restart the engine—ideally, it should idle smoothly and without stalling. This would confirm if exhaust restriction is causing hot gases to enter the intake. \n\nFaldih Higgins, Diagnostician | Autocom SA