Might want to check your vaccum hoses. Sounds like a leak, maybe on the vaccum advance
Is anyone on line to help me with this question? Where is the fast idle thermal valve in a 1997 Chevy astro van located?
it controls idling of car engine, without it it will not idle..
A 1998 Chevy Prism's idle speed is computer controlled. You will have to take it to a garage to get it set. However, the idle speed could be altered if, say, your spark plugs are seriously worn. Changing them may restore the original idle speed.
time to replace the pump and rack and pinion sector
98 chevy lddle control valve
The IAC (Idle air control) valve is bad and needs to be replaced. Its about $200 parts and labor.
IAC (idle air control) valve may be bad. Located on the passenger side of the throttle body.
Check the Idle Air control valve. This lets air bypass the throttle body plate when the car is at idle or low revs.
Possible bad battery, check for >12.4 VDC at the posts after a overnight rest. Possible bad alternator, start car, check voltage at the posts, should be 13.8 to 14.0 VDC at fast idle.
That engine is computer controlled therefore the idle was preset / calibrated from the factory and there is NO adjustment. You need to have the engine scaned with an engine scanner to see what is making it Idle to fast. Check for vacuum leaks first.
you need the fast idle adjusted on the engine you may have idle set where it sounds fine in idle but not high enuff when dropped in gear.
there is no "fast idle solenoid" there has'nt been a fast idle adjustment on passenger cars in over 20 years