Thread: Jumpy RPMs when accelerating.

I am not sure what is causing my issue but it is annoying as all can be. When I am trying to accelerate I notice that when the car shifts & trys to go faster the RPMs will will randomly jump around, then be fine. It doesn't feel like the transmission is slipping but I don't know what it is doing either. It seems like the car is trying to speed up but doesn't want to, eventually doing so with no problem.

It doesn't do it all the time but I noticed it real bad the past couple days when it was real wet out. It does it at the same time every time. I think around the 1800-2000 mark in 3rd.

I noticed someone had a post in the transmission section but I don't think this is transmission related.

The car is a 2008 Grand Prix, 3800 engine with only 34700 on the clock. Could this be a sign of a coil or module that is going out?

Have you taken the vehicle into your dealer for an inspection yet? I see that you are on the cusp of the warranty by mileage, how about by date? If the vehicle is still under warranty, you may be able to have the issue repaired under warranty. I would suggest making an appointment for a diagnosis. The dealer should be able to pinpoint the problem with better accuracy. If you have any further questions, please feel free to contact me.


Louis
GM Customer Service

Originally Posted by GMCustomerService

Have you taken the vehicle into your dealer for an inspection yet? I see that you are on the cusp of the warranty by mileage, how about by date? If the vehicle is still under warranty, you may be able to have the issue repaired under warranty. I would suggest making an appointment for a diagnosis. The dealer should be able to pinpoint the problem with better accuracy. If you have any further questions, please feel free to contact me.


Louis
GM Customer Service

It's actually past the warranty date by about 8 months. Got the car a couple weeks back & when I test drove the car I didn't notice any issues but it isn't something that shows up in a short drive either.

Originally Posted by Explicit_Spade

Sounds like your maf may be dirty or need replaced. It may also possibly be a bad gasket causing a vacuum leak.

Hmmmm... I'll take a look at that to see what I can find out. If anything I might locate a known good sensor & hook it up to see if it acts any different. As for the vac leaks it shouldn't be too hard to find if there is one.

Haven't checked the MAF sensor yet but one thing I am gonna go ahead & do is pick up a few ignition coils & swap them out. I figure I'll go to the junkyard to get them since they are dirt cheap there. It seems more & more like a coil acting up so I figure might as well try it. Worse case scenario I got some extra coils in case any goes bad.

It turned out to be some sensor inside the transmission that was bad. I was in denial that it was going to need replacing but when I took it to the dealer they confirmed it was bad.