High idle For years I've experienced a sporatic and widely variable (i.e. 750-1700RPM) idle when the engine is warm. Many mechanics have tried to ID the source of the problem. Usually they say that the throttle body is dirty and needs cleanings (which I've done probably 3-4 times in the past 6 years, with no improvement. About 1 year ago, a mechanic (not the dealer-they could never fix the problem) discovered that the setting on the ICM / senor was WAY off. He adjusted it and the car ran great until...1 year later, when the same problem started again. I'll feel the car (2000 Legacy GT wagon) tugging at me at a stop light, shift the car to neutral and watch the idle fluctuate between 600-1700, with occasionaly missing. Sometimes shifting the car back to drive will almost cause it to die. One other recent development is that the temp gauge will sometimes read high during these events, although once the cooling fan kicks on, the temp will moderate. No apparent loss of coolant. Car has about 96,000 miles. Any ideas? Thanks....

new engine might already be experiencing "blow-by".
search for a manual and check compression values. then have a mechanic perform a compression test on your engine. if result is much lower than expected, then try replacing piston rings, valve guides, and valve seals

try this simple test
start the car and hold at around 1000 rpms until the engine warms up
now place it in gear with the handbrake on ( don't touch the foot brake
if it is idling at around 800 rpms and is smooth, apply the foot brake
if it plays up , replace the brake booster as there is a vacuum leak upsetting the idle mixture setting
recheck by allowing it idle in neutral with the hand brake on and the apply the foot brake

same thing happened to me, i do know my s 10 durango's problem was with the intake gaskets etc and the carburator, and the timing was off, i got the carb rebuilt and an overhaul put on it, its just timing issues, when you start and it high idles, tap the gas after a min of it being started and it'll slow down a lot and be normal, it high idles after being parked a while to warm up is what my mechanic told me mine was an 84, is yours carburated or fuel injected?? take it to a mechanic and get a diagnosis that would be your best bet, and about two months after mine doing the same the engine blew on me and it was three grand to fix, so i sold it, and it bley black smoke worse than a diesel, and it was gas, and you might get a hard knocking sound soon too, if you drive it really hard, is it a 2.8 L V6?? thats not a very good engine design anyhow, its the same as my s 10 if it is, any it'll probe die soon, happened to my friend the exact time that mine did and in all the same stages, but we drove like dumb teenagers, it was just last year, best of luck

your idle problem is because your carb is missing somelines such as vacuum etc.
the reason your top up is increasing is because your car is burning oil hence the white/blue smoke.
you need your head gaskets changed and also get your mechanic to take a look at your O-rings (piston rings)

Check all the vacuum hoses and see if they are broken or disconnected. Surge in power issues, idling issues, engine stall while driving, all are related to vacuum hoses. Give a try.

You could try replacing the idle air control valve but I would obtain one from a local salvage yard, its cheaper and you are not certain if thats the problem, another thing i would check is your intake manifold gasket where it meets the cylinder head, if tha gasket is cracked or leaking it will allow excess air to enter the engine and make it idle higher, the easiest way to verify this is get a can of carb and choke cleaner and spray it all around the intake gasket area, if the engines idling characteristics change drastically then the gasket is bad and needs to be replaced if theres no change in the idle I would start looking for vacumm leaks and the idle control valve issue, which you specified.

Your car may not have recieved a recall on 02/201998 on the vehicle speed control recall id from NHTSA98v035000. the throttle shaft ball bearings on the sensor side of the throttle body assembly was not insalled in certain throttle bodies. Operation of a vehicle with a missing throttle shaft bearing can eventually lead to an incomplete return of the throttle valve resulting in a high idling condition. 61115 vehicles were affected. Take vin number to dealer see if your vehicle has been inspected for this missing bearing.

You need to clean the throttle valve and the idle speed control valve, they get sludged up and cause this issue. Get a can of throttle valve cleaner from your local parts store, pull off the rubber flex air intake hose and start engine, have someone hold engine at high idle while you spray the contents of the can into the intake, when the can is about 1/2 empty let the engine stall, disconnect the battery for 30 minutes and then restart, quickly push the throttle wide open a few times to blow out any loose sludge, and that should cure your stall.

The high idle is caused by the choke and the high idle on the carb. It is working normal and you do won't to warm up this motor before going. When it is warm and you hit the gas it activates the choke pull off to bring the idle to normal. Your mechanic is used to fuel injection that will control the fuel/air mix according to temp. I still let my injected cars warm up so the oil can thin a little. If you jump on the highway with cold thick oil it can all wind up in the to of the motor.