Base off of what you say, I would say it is your fast idle valve. I have provided what the valve does and a check you can do.
The Fast Idle Valve, mounted on the throttle body next to the throttle angle (TPS) sensor, raises the idle speed when the engine is cold. The Fast Idle Valve is controlled by a thermowax plunger type valve. When the engine coolant is cold, the thermowax contracts the plunger which opens the valve allowing air to bypass the throttle plate and idle adjusting screw into the intake manifold. When the engine coolant warms up, the valve closes and the bypass air flow is blocked.
NOTE: Do not attempt to disassemble the Fast Idle Valve, it is factory adjusted.
Start the engine.
Remove the cover of the fast idle valve.
Put your finger on the valve seat area and make sure that there is air flow with the engine cold (coolant temperature below 86 F, 30 C) and idling.
If there is no air flow, replace the Fast Idle Valve and retest.
Warm up the engine to normal operating temperature (the cooling fan comes on).
Check that the valve is completely closed (no air suction can be felt in the valve seat area).
If any suction is felt, the valve is leaking. Replace the Fast Idle Valve and recheck.
Saturday, October 25th, 2008 AT 12:51 AM