chris_w

I'm driving down the freeway, doing a constant 65. I'm not accelerating or decelerating much, just kind of keeping the car's forward motion. About three times it "bucked", I don't know how else to describe it, like a slight shudder. The first time I thought it was road imperfections, but then i closed the roof and shut off the stereo and the effect was much more pronounced since I was paying more attention.

I had about a quarter of a tank of gas in the car, so I went ahead and filled up at the next station. The car is still doing it, though not as much. Before I take it to the dealer, can anyone back me up that I just got a bad tank of gasoline? I have already had my transmission replaced (about 2k miles ago, and I have 22k on the car now).

Thanks! Chris

copland007

Sounds like the tranny again, sorry man

copland007

Oh, to answer your question. Since the car has a knock sensor the most you would be able to tell is a slight pinging trying to accelerate or under heavy load like going uphill. The knock sensor would stop it pretty quickly though. I don't think that's what you are experiencing

chris_w

To follow up, it was almost like the car was running out of gas (this happened to a friend of mine's Alero just last weekend and the sensation, while not as abrupt as his, was similar). I just can't imagine that the transmission took part in this because I wasn't doing anything that would involve it.

Would the car's computer register a problem that the dealer might be able to check? Wouldn't that trip my Check Engine light?

copland007

Most likely no codes, and believe me I didn't expect my disasterous tranny failure either

Was the tac really low? Could it have been the torque converter letting go of its lock?