Listen and look for a vacuum leak. Could be anywhere.
idles at 3000 will not go down 1993 grand prix gtp
Not adjustable. Sounds like the throttle position sensor.
worn out spark plugs.
A good chance its the Idle Control Valve
crankshaft sensor going.
I also wish someone would answer this question as my 1997 Ford contour does the same thing. It shakes and vibrates very bad when it idles and it idles really low. They set the idle up to make it so it wouldn't die so now when I start it it revs up really bad then it idles down then it idles down to low and shakes I also wish someone would answer this question as my 1997 Ford contour does the same thing. It shakes and vibrates very bad when it idles and it idles really low. They set the idle up to make it so it wouldn't die so now when I start it it revs up really bad then it idles down then it idles down to low and shakes
It could be a dirty air filter or a dirty throttle body.
Start the engine, and spray a little carb cleaner around and on the EGR valve. If the engine changes sound are idles up are down then the valve is bad.
check for vaccum leaks.
Could be a plugged catalytic converter or bad coil. Both will act up when they get warm.
Probably a bad idle air control valve.
Either the fuel mix is adjusted wrong or the carb is dirty