2001 Chevy Malibu w/ ~81,000 miles. When I press the gas conservatively, the car accelerates fine up to about 15-20 mph then it starts getting sluggish and sort of jumpy. By " jumpy" I mean that it feels like its either not getting gas or not burning the gas that its getting. I don't want to say that its misfiring because I don't know for sure if it is. The fastest I go to and from work is 40 mph and its tough to get up to that speed. This problem is more noticeable/severe when pressing the gas liberally or when attempting to accelerate or keep a constant speed going up a hill. I just had the intake manifold gasket replaced and the fuel filter replaced. Every garage that I call or stop at says it could be any number of things from plugs and/or wires to fuel pump, to catalytic converter, and so on.
Thanks, I forgot to mention that the guy that changed my intake gasket checked the fuel pressure at idle and it was Ok. He did not check it while driving (I guess he didn't have the right tool for that).
Another thing that I forgot to mention, the problem seems to be less evident the colder it is. On cold mornings, if I get in and drive to work (about 5 miles), its not so bad until everything warms up to normal operating temp. But last week we had a few below freezing days and I would have never guessed there was a problem at all. It drove without any problems whatsoever.
I'll see if I can find someone to check the fuel pressure while driving but in the meantime, I'm still at a loss here.
December, 22, 2006 AT 2:09 PM
To anyone else watching this post or for future viewers.
It turns out the problem was my catalytic convertor. The part was about $210. I was prepared to have the fuel pump replaced when the mechanic took it for a spin and advised against that. He commented that the fuel pump usually stops working all together so I wouldn't have even been able to drive the car in.
After replacing the convertor, the car ran like normal again.