Acceleration Problem 2001 GT

well, here I am almost two years later and I think I'm starting to have the problem I had before again.. not nearly as bad, but my car has seemed to gradually be getting less performance and gas mileage. (2001 GT) It used to always get 30mpg or a little above for an average, most of my mileage is highway.. and I've never had any problems with power even the steepest hills, never had to be easy with the gas it just rolled right over anything.. but now I'm getting more along the lines of 24-27mpg and often on hills it seems to need quite a bit of pedal to keep going. A few times I've started my car and gotten something out of my trunk, etc,. and I've noticed very strong sulfur smell which gets me worried about the cat. Then the other day I called the dealership that originally fixed the car and nothing is under any kind of warranty now, dammit, (104,000 miles) and the only thing they have listed on their ticket as being replaced is the catalytic converter.. no PCM? or whatever the guy called it after I picked it up. (don't recall ever getting an actual ticket, I was just so glad it was fixed and for free,.. can't find it now.) So I'm not sure if the guy was feeding me crap or what. Seems like they should have replaced the computer because that's why the cat was bad in the first place.. that's what they told me. Anyone have any ideas on this? The "all-knowing" secretary I was talking to said there was NO way that the computer could affect things to make the cat go bad.. Sounds to me like they swapped the cat and it seemed good so they called it fixed. ????

The converter warranty was exended to 7 years, 120,000 miles on 01-02 Grand Prix's due to a known issue with the converters breaking apart internally and plugging up. Get to your GM dealer ASAP!

Due to the age of your original thread and problem your post has been moved to a new thread.

The original thread at link below has been closed.

http://www.automotiveforums.com/vbulletin/showthread.php?t=236313

sorry, my answer is not valid as I misread the post as you replaced the PCM, not the cat. You never mentioned whether you've replaced tune-up parts such as plugs, wires, fuel filter, pcv valve, etc... If not, you're overdue.

I have replaced the fuel filter, all plugs, the wires were replaced last time I had the problem (about 50,000miles ago) ... the air filter was overdue so changed it out. I think that is probably it... I didn't think about the egr.. hmm.. Everything has seemed alright when I changed it so far.. nothing obviously wrong. I ran an OBII test on it and came up with nothing.. Well, I guess I'll just keep an eye on things.