I am hoping someone on here can help me I am having some major problems with my 03 Monte Carlo SS. I have spent hours on here looking and reading and some stuff is similar I am not really finding anything super close to the problems I am having. The check engine light is not on however the ABS light and Traction Control LIght are on for a faulty Front Right Speed sensor. I do now know if that will cause all of the below or not.

Mechanics around me will not look at it as they are calling it an intermetent problem and without the check engine light being on it would take to long to diagnose if they could at all.

130,000 miles on Car
Car Starts and Idles Fine
Car is shutting itself off at Speed Car Still has Power to Everything Just Shutting itself Off
When it stalls it will restart as soon as you put the car in park will die and than as of now run again until it decides to stall again.
When pressing the accelerator to get up to speed the RPM will jump back and forth untill you release the gas pedal and slowly push it back down.
When you take your foot off the accelerator the engine RPM does not drop and car does not lose speed until 5 or seconds and then it will lose speed and RPM's will slowly drop to normal.
Car feels like it misfires right before it stalls. As soon as I take my foot off the accelerator the RPM's will drop to zero and stall
The cars shift points feel off.
Here recently the car is not realy wanting to shift at all and the RPM's are way off think 3500rpm at 30 MPH and no throttle response at all. And the car does not feel like it is at 3500 rpm's it just thinks it is.

Can anyone point me in the correct direction please.

Eric

 

Started the car today let it warm up to temp car was idling fine around 700 to 800 in park. Drove the car around was able to reproduce the rpm going up and not coming down but not the stalling. Got home put car in park and it is now idling at 1500 and eventually 2000. Turned car off let it sit a few minutes restarted and back to normal.

 

First items to start with, is the car throwing any check engine codes? If so, can you get it scanned and report back what they are?

 

no codes according to the scanner tool. I appreciate the answer.

 

I would start testing sensors/reading data on them to see if one or more are malfunctioning. Do you do basic maintenance on the vehicle? Ive had similar problems with bad MAFs or IACs. ..Or a big vacuum leak.

 

I'm with whtmonte - Id pick up a scan tool that can read live sensor data. IMO its as essential as a screwdriver or ratchet when it comes to working on modern cars.

I agree with either vac leak or IAC being one piece of it - if you close the throttle and the engine rpm doesn't start coming down, its clearly getting air from somewhere other than the throttle blade (assuming the TB is clean / not getting hung up). Id probably lean more towards IAC from your second post - if just shutting it off and turning it back on magically makes it go away.

But thats an awful lot of symptoms for it to be a single problem, I suspect there's more than one thing going on here (or maybe one problem that cascades into others as the pcm tries to compensate).

 

Bumpin and Whtmonte are on target.
One "poor man's" diagnostic you can do to check for a vac leak, get a can of starting fluid and mist it around the engine while it is running and all areas for a vacuum connection or seal. Listen for the idle to change. If it changes as a result of the mist of starting fluid, it is sucking that fluid in through a leak.

I could throw random ideas.... Like plugs could be a factor, especially if they are still factory original. As mentioned, could be the IAC having a problem. Check and make sure the air filter is not clogged. Maybe even a MAF is at play here.

The big odd part is to have these many symptoms and not throwing a code. That being said, it is a problem, but the computer believes things are running within parameters.

 

I ended up taking it to a shop to see what they could find the are telling me a bad MAF, THe thermostat is not working correctly always open and it is throwing code PO730 and the code is for the transmission they say it is slipping and can hear a bearing and needs replaced.

Can the bad MAF and the Thermostat cause the above issues?

 

A bad MAF has been known to cause random stalls and some other performance issues. You can disconnect it (which the car is off) and see how the car runs. If it runs fine, then a good chance the MAF is a potential problem and should be replaced.

Keep in mind, the MAF does get involved in fueling.