Hello Chevy Forum.

I am having a problem with my 2007 Chevy Impala Automatic LT. And I hope someone can help me out with finding the answer. I purchased the car preowned with 14,000 on it. About 28,000 I noticed the RPM's are sitting up higher when starting the car and even while idling. I took my car in to get the 30,000 mile service done and told the tech about the high RPM's and they told me I would have to come back and talk to the tech person that takes care of transmissions. So that's another appointment I have to make.
So anyones input would be great.
Thank you

 

sucks.
Does it do this only in Park/neutral? or also in Drive/idle

could be that the thermostat is not closing and the engine is remaining in cold engine mode (higher RPMS's)
What is your temp gauge sitting at?

 

Thats what I'm thinking too. It should tach around 1100 when the engine temp is below 190-205 F.

 

It does do it in idle/park. The car warm up normally and doesn't run hot. The temp gauge hasn't changed. I quite positve it isn't the thermostat because I had that problem on my previous car.

 

If it does it when its warmed up, then there is a problem. If it does it before it warms up, its normal.

 

For up to the first 30 second of start up especially when cold the PCM will be in open loop. While in open loop the idle will be higher. If after this period the idle is up then something is definatly wrong. If not then it is normal. If it is still up it absolutly not the transmisson. There are many possible causes some of which are a vac leak, bad IAC (idle air control) bad TPS (throttle position sensor).

 

How about a build-up of "carbon-sticky" on the IAC pintle? But still low mileage for somthing like that.

 

thanks guys. I'll mention all this info to the mechanic when I get the chance