Ok, I am trying to chase down an ongoing problem with my daily driver and hopefully you guys can help.

The car is a 2001 Chevy Malibu LS with a 3100 V6 and 4spd auto tranny (4T40E).

The problem started out as a surging from the enigne while cruising. If I was cruising ar 55MPH the engine whould jump in RPMs about 200-400RPM and then settle back down to normal RPM for 55MPH (I honestly cannot remember what this RPM would be its been so long since I have seen it). The problem gradually became more and more common and would happen at peeds between 40 and 80MPH. My Father-In-Law suggested I put a bottle of TransX in to clean up any stuck valves and selenoids. This did not fix the probelm. The problem has continued to the point it is at today. At speeds between 40 and 80MPH the RPMs are higher than the should be no matter the driving conditions. Say at 50MPH, the engine is turning at 2100RPM, 60MPH gives about the same RPM, around 70MPH it is 23-2300 RPM. Its as if the tranny will not fully shift into OD.

I have done a lot of research online and have come up with several possible causes.
1. A bad TCC selenoid
2. A leaking drive bearing gasket
3. a dirty MAF sensor (this was cleaned several time to no avail)
4. A PCM that needs to be reprogrammed (problem returns after PCM relearns the shift points)
and several other probable causes that did nothing to correct the problem.

One of the best reads I have found is here on the GrandAMGT site.

Please let me know what you guys think this might be. I really can't afford to bring it to a shop for repairs right now. Hopefully after Christmas I can get this worked out. And it is really killing my gas mileage. I have gone from 26-29MPG to about 20-22MPG, maybe less. I have been so dissapointed that I just about quit tracking it.

Thanks in advance guys.

Chris

check engine light on? what is the mileage? best advise is to have a scanner and good test drive with a good tranny shop tech. no easy answer without any more information.

We have not seen this problem,yet however we did have a 4t40e in last year that had an issue with tcc duty cycle, this was a logic problem with the computer.

Just going by what you have described, it would seem that the computer in your car may need to be "flashed".

There are no lights on and no codes being thrown. Which doesn't help any. The car has 134000Miles on it. The tranny was fully flushed and filter changed around 80K miles. Other than that it has seen no service.

I agree, I doo need to take it for a test drive with a tranny tech, the hard part there is finding the time to get it done.

From al that I have read, having the PCM flashed only cures the problem for a short period.

I apreciate the help so far guys.

Chris