Heavy deceleration after letting off throttle
 

Hi guys,

Since I bought my car I've noticed that when I left off the throttle in 1-3 (mainly 1st and 2nd) the car decelerates kind of jerky.

I understand it's going to decelerate more when letting off gas than say an auto, but it's very jerky.

I recently cleaned my CAI filter and after that the jerkiness stopped for a little bit and then started again.

I also noticed after doing so most of the pop back from the exhaust had stopped, but again that is back as well.

My car is 2008 with 80k and a Cobb CAI and a Freddy CBE. There's no AP, but I'm curious if the previous owner had one and was running a time.

Any ideas?

I've seen people complain of jerkiness when letting off and other recommend a RMM (which I plan to do) but cleaning the CAI has nothing to do with that and it helped.

Any help is appreciated!!

I should have titled it jerky deceleration not heavy...sorry

@StopaOcean; How much experience do you have with manual transmission cars? Is this your first? How long have you been driving it?

@msms3 this is my first manual car, however, I've driven manual probably around 20 times before on friends cars. I know that isn't a whole lot though.

I understand there is going to be heavy deceleration, I worded that kind of bad. My issue is just how jerky it is. I just feel like it's odd that as soon as I cleaned the intake the jerkiness disappeared for a bit. Maybe this is just how these cars are and I'm not that experienced.

That's why I wanted to hear from others.

Check your rear motor mount. If it's bad, you can actually rock the engine fore and aft by just grabbing the oil pan.

Thank you, will do.

Letting up on the gas completely in first gear will be abrupt, a little less so in second.

Given your explanation, I’m inclined to agree with the suggestion that you have a failed rear motor mount. It’s a relatively inexpensive part and easy to replace. There are how-to instructions on that here.

If the car runs just fine, otherwise, your CAI filter cleaning has nothing to do with it. Just coincidence.