General malfunctions of the automatic transmission throttle valve
1. Malfunction of the throttle position sensor (TPS)
* Incorrect throttle position readings
* Fluctuations in engine speed / dips during acceleration
*Check Engine light comes on
2. Malfunction of the mass air flow (MAF) sensor
* Incorrect air flow readings
* Problems with air/fuel mixture control
*Loss of power/reduced fuel economy
3. Throttle valve dirty
*Deposit accumulation on throttle body
* Poor throttle response
* Fluctuations in idle speed
4. Malfunction of the fuel pressure regulator
* Incorrect fuel pressure
*Rich/lean mixture of air and fuel
*Difficulty starting the engine/loss of power
5. Faulty Idle Air Control Valve (IAC)
* Incorrect idle speed control
*Idle speed fluctuations/stalls at idle
6. Breaks or poor contacts in electrical wiring
* Breaks or poor connections in the wiring harness
* Unstable engine operation
*Check Engine light comes on
7. Malfunction of the engine control module (ECM)
* Problems with throttle control
*Many throttle related symptoms
*Requires professional diagnosis and repair
Possible consequences of automatic transmission throttle valve malfunctions
*Loss of power and decreased fuel economy
* Fluctuations in engine speed / stalls at idle
*Transmission problems such as hard shifting or slipping
* Engine damage due to uncontrolled air and fuel consumption