'09 GT Rough Idle

[gjswaff]

My '09 GT (2.4L) started idling rough just after I change the battery. Very bad at first, then it got better, but still idles like there is a vacuum leak somewhere. At first I thought it couldn't be the battery, I mean one has nothing to do with the other, right? Also, when I had the oil changed, the mechanic noticed a small leak on the valve cover gasket. Could this have anything to do with rough idle? Newer engines are so complex! There is no check engine light, but the vibration is annoying. My GT has about 95,000 miles.

[gtv237]

It's probably just relearning the idle after the battery was disconnected. You can wait a little while and see if it improves or you can disconnect the battery again to delete any bad habits in the idle.

[gjswaff]

Thanks gtv, tried that but it didn't work. Had mechanic reset the codes, that didn't work either. The idle is not rough so much as the vibration. It's really bad especially while in gear with the A/C on. Otherwise, my vibe runs great. I was hoping to avoid taking it to the GM dealer, my last resort. Motor mount maybe. I seem to remember a Camry or Corolla I had years ago that had that problem.

[Dairgo]

My '09 GT has always had a rough idle / vibration since I purchased it a few years ago. I've had my mechanic look at the motor mounts, and they were fine. Not sure what else to do, other than confirm that it's not JUST your GT. If you put it in neutral does it go away? Could that confirm something with the transmission or something?

I know I have possible issues with my torque converter on my transmission (hard down shifting into 1st when slowing down some times, but not consistently to the point where it happens ever time or every day).

[gjswaff]

Thanks Dairgo! My Vibe used to idle just fine. It seemed to start vibrating right after I replaced a dead battery. I didn't think that anything to do with it until somebody told me about the codes needing reset. But, that didn't really help either. The front motor mount looks to be bad so I'm going to change that. If that doesn't do it guess I'll take it to the GMC dealer and have it looked at. But I'm guessing that will cost a bunch.