I am a recent owner to a 2003 Monte SS, I have owned the car for about two years now. And have been having problems with the car in the winter months. When it gets cold outside the car seems to stick at a higher RPM's even when first started and when it has been running for a while. At an idle it doesn't want to drop below 1200 RPM's after it is completely warmed up. One day it even stuck at 3,000 RPM's which of course makes it just about impossible to drive!! I have had a mechanic look at it and hook it up to his computer, the only thing that the computer read was that the thermostat wasn't opening fully, so they replaced that and it seemed to be working fine for a few days and now its back to being the way it was! and now the check engine light came on. I have had a few people tell me they think it may be the throttle body position sensor has gone bad, i know the mechanic looked and did some tests to see if there was a leak near and around the throttle body and they found nothing! help anyone please!!!!

 

i know this is going to sound rediculous...but the fact that it was reading that the thermostat was stuck open made me wonder...its exactly what my old vehicle did when it needed a new coolant temp sensor...sounds funny..but it could possibly be the cause of the problem....worth a try to check that

 

Check for intake manifold for leaks.
also if you have an autozone near you they will hook up a scan tool (free of charge) as long as the light is on. They will at least point you in a dircetion of what might be causing the problem. .

Get a can of wd40 and spray it around the intake where it meets the heads and block, if you hear the engine change then you have an intake leak. Check vaccum lines as well

 

Josh I was thinking the same thing.

jaime_6798 does your temp gauge work?

I was thinking the leak in the manifold or vacuum leak too. Just for kicks and giggles, check to make sure that your intake hose is securely attached. My mother-in-law had the same problem on her buick and come to find out the air filter box wasn't latched and was hanging open.

 

Yes the temp gauge is working properly, that is why we didn't recognize at first that the thermostat wasn't opening properly, because it was always decently warm heat coming into the car and it never went above the half way point on the gauge.

 

Is the cooling sensor the same as a cooling sending unit?

 

have your mechanic check to see if the coolant sensor is reading properly. what your gauge says and what the pcm is reading could be completely different. what happens is for instance if the computer is reading the coolant to be at a very low temp even if you know the engine is warm, the pcm is going to dump a lot more fuel. at the same time it will also add much more air resulting in a very high idle. also check to see while the scan tool is connected to see what the voltage is with the oxygen sensor. it is possible in open loop all the time as well as reading low temperature. i guess what i am trying to say is have a technician go over the pcm again and see if something is not jiving. while he is in there have him run a smoke detector into the vacuum lines to see if it has a leak or not. LET ME KNOW.

scott

 

I still say it sounds like an intake leak..... I know the coolant sesnor can do strang things but Im still pushing intake or vac leak

 

i would look in this order for things.
intake leaks, this can also be checked by seeign the fluid level is in the same place for a set time frame while driving.
I would check to see if you can find a test for the temp sensor. im thinking it is not readding it correctly.
and i would check the throttel position sensor.

here is the issue. with todays guages etc. they are run by the computer not liek the old guages that had a sensor on the end of a wire straight to the back of your dash.
So even if the guage is reading correctly it could be getting a false reading from the sensor . and this is why your car is not ideling down.

also if the throttel sensor has gone bad or in been moved it might be readdign it in the wrong position . agian this would snd the wrong signal and caus eit to rev. higher then needed.

if you have a intake leak it will casu ethe water level to lower in most cases. and aslo it will create a false reading and could be why this is happeing for you.
has your car been in for the recall? they had a recall on the lower intake gaskets on our cars and they would leak. this could be all apart of this . if it is then you might have it done free for you from teh deaership :-) this is always a good thing.
let us know wha tyou find out on this. but this is wha ti would start looking in to.

if i had my manuals here still i would attempt to look it up for ya. but they are on thier way back sorry.

 

Does anyone know, since I bought the car from a used non-chevy lot, if they dealerships will still do the recalls, because i know that there are number of them for my monte, but I have never been notified of them because of buying from a used car dealer? Also, do they usually give you a rental car if there is a number of recalls to do on the car?