inspect the distributor gear.
Is anyone on line to help me with this question? Where is the fast idle thermal valve in a 1997 Chevy astro van located?
check vac hose's for damg. or hole
change ur air flow meter its on ur air box pipe
vacuum leak, bad idle control sensor
i would change the spark plug wires
e.g.r. valve replacement fixed mine. symptoms where rough idle and "surged".
Idle Air Control Motor malfunctioning.
The idle is automatic. If the speed is not corect then you have to fix the problem with the idle motor.
Your distributer or your coil
Does it miss on acceleration or at idle? If on accel I would be looking at the plugs and wires
Idle is computer controlled, there is no adjustment screw.
An obdII code reader will tell you why the light is on and might tell you what is wrong