My olds silhouette has a high idle and havent been able to correct it. If you shut if off and turn it back on, sometimes this helps but not all the time. How can this be remedied?

It's called IAC - idle air control valve > Did the RPM'S stay at 2000 or drop back down ? The PCM engine computer controls IAC valve according to engine load . Put it in gear , turn on electrical loads , headlamps , A/C etc... an the RPM raise's up so engine will not stall . More then likely the throttle plate needs to be cleaned , they get gummed up an stick at higher idle . Quick Tip Throttle Cleaning EricTheCarGuy If the IAC valve were gummed up the idle would be low or erratic . On some engines a vacuum leak will cause high idle . Videos on youtube checking for vacuum leaks .

First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

MAP manifold absolute pressure sensor may be bad .

Well you have a three part question...so part one the engine whats to shut off when you turn the wheel>there is a steering pressure switch located on the power hose line running to your power steering pump,,,it has an electrical connector make sure it hasn;t come loose or fuild leaking at base of switch or on top by connection...this switch sends a signal to your computer to increase the engine speed when the wheel is cranked so it doesn't stall ..Number 2 while driving shuts down can be a number of things but sort of relates to Number 3 idleing high sometimes...On your throttle body there is a component called a IAC sensor [idle air control} it should be tested sometimes the oring seal goes bad...also check condition of your air filter,if your vehicle has a MAF sensor {mass air flow } it also could be dirty....so with your air filter off and engine running spray some THROTTLE body cleaner into the opening of throttle while increasing the Rpm's of the throttle...Hope this leads you the right way

it sounds like its drawing air into the inlet mannifold

I had a the same problem with my 95' Silhouette it got worse and then would not restart until it cooled off. the problem is most likely the crankshaft position sensor this is what resolved my issue.

Set your idle speed to mfg recomindation if that doesnt help check the dash pot that is what keeps the engine from stalling at sudden speed reduction

Seems like an idle speed control to me.

sounds like the idle air control motor is sticking , not sure what engine you have 3.4 litre ?? also you can ck the throttle plate right on top where the throttle cable bracket assembly part of that bracket holds down a vaccum line that has a rubber gromnet that after time leaks causing idle surge , hope this helps

Hello two major culprits off this is your TPS sensor wich controls the idle what you need to look at is when you start the car does the Rpm needle stay in a semi fixed position give or take a couple of lines or does it idle erratic it should be at a semi fixed if erratic it probaly is out of range you can test with a ohm meter if not autozone offers free testing on sensors The second problem wich sometimes can not be detected by a scanner and doesnt always set a hard code is your IAC motor IDLE AIR CONTROL VALVE wich is inserted internal into your throttle body on the end of this has a top shaped piece wich plugs a bore hole internaly inside if this is built up with carbon or varnish it binds internally causing higher idles, lower idles ,stalling, nostarts ,hesitation,rough idle, etc this mounts with usually to torx shaped screws also can be tested with scanner but dont rule this one out it can retract and extend register fine to the computer but bind internal with out ever setting a code goodluck please rate thanks