Is the check engine light on , or any other lights ?
- Unique Idle Concerns:
- Additional Drivability Concerns:
If vehicle runs normally after the ignition key is turned OFF, check for damaged ignition switch, IGN RUN circuit short to power, VPWR circuit short to power, etc. Refer to applicable Wiring Diagram and/or Workshop Manual.
REFERENCE (Section 5 Pinpoint Test unless noted)
- Base engine air leaks, including proper sealing of intake manifold and components/vacuum lines attached to intake air (such as the PCV, EGR or IAC valve/vacuum lines).
- Visual, Engine System - General Information Section 303 of the Workshop Manual.
- Verify engine operates at normal temperature.
- Visual (refer to Symptom Index, or Engine Cooling Section 303 of Workshop Manual, to diagnose any cooling system concerns that are present).
- Fast idle concerns:
- Key on, engine off, monitor TP MODE PID while wiggling TP sensor circuits. TP MODE PID can also be monitored during vehicle drive. With throttle closed, TP MODE PID must be C/T (closed throttle).
- TP Mode PID is not C/T with throttle closed:
NOTE: At vehicle start, the TPREL will begin at about 1.25 volts, and count down to the lowest TP V value seen since engine start. If the TP V value goes below the "normal" range, then increases again, TPREL will set to the lower voltage. If TP V is about 0.04 volts greater than the TPREL value at closed throttle, the PCM will go into part throttle mode.
- Monitor TP V and TPREL PIDs for sudden changes while checking for intermittent TP circuit/connector concerns. Also check for loose/worn throttle plates. If no concern is found, GO to Z1 in Section 5.
- Intake Air System (air leaks)
- Idle Air Control (IAC) System
Do you know what these thing's are that I have listed above ? Mostly the TP - throttle position sensor . These are known to cause this type of problem . Has it ever been changed before ?