Eric052492

Hey guys,

I am having an issue with my engine RPM's fluctuating like crazy when decelerating. It just started happening today. First some backstory. I have a 2010 GT (auto) with a JLT intake, bama tune, and pype bomb exhaust. I cleaned and re-oiled the filter about three months ago. I also just had the differential fluid changed about a week ago (just trying to give as much info as possible for recent changes.) So far I've checked the intake for any vacuum leaks but everything is snug. I also took a peak inside the throttle body and everything is clean there. That leaves me with two more theories. A. The MAF sensor is dirty/oily and needs to be cleaned. B. I didn't oil the filter enough when I last cleaned it. I will post some videos below of the problem and any input would be greatly appreciated.

Thanks in advanced!

In both of these videos, you can see that accelerating and cruising causes no problems, only deceleration. The first video is around 70mph and the second is 70 - 0.

AMDanBailer

Hmm.. this looks very odd. I'm not exactly sure what could be causing this. However, you're on the right track to getting this fixed. I would definitely look into the MAF next. If there is something going on with the MAF, it will definitely cause some issues for you.

I would start with that and see how you make out. Have you ever had any issues with the Bama tune? I don't think it's related to the Tune but I don't want to rule out anything just yet.

-Dan

Eric052492

Thanks for the response Dan. I cleaned the MAF and redid all the fittings on the intake but no luck. The tune has always has a very slight RPM fluctuation when idling but it has never affected the car while actually driving. I wouldn't mind trying a new tune to see if it solves my problems. I honestly can't think of what else could be causing the problem. There is still a slight RPM fluctuation when idling but now (as the videos show above) it happens when decelerating as well.

- Eric

6bangr

I had a similar issue on my 01 stang with a 93 octane tune, a different animal I know. While decelerating it would do the exact same thing, it got so bad that it actually stalled out a few times. I replaced a lot of sensors trying to figure out what it was (IAT, TPS, even the MAF), none of it made a difference. I final took it to the dealership and they thought it was the charging system and suggested a new alternator (the car was only 6 years old at the time). I was willing to try anything at that point, so I went for it. Sure enough the problem disappeared after they replaced the alternator. It might be worth while to at least check the charging system too. Just my 2 cents...

Nuke

Although the TB "looks" clean, I'd still remove it and do a thorough cleaning. It doesn't take much to throw these S197's off.

Eric052492

Hmm... I will try and clean the TB when I get a chance. I'll make sure to update this thread when I do. Hopefully I'll have it done by Thursday (when I have some free time.) If that doesn't do the trick, I may pursue what 6bangr recommended and get the alternator/charging system checked out. Do you remember exactly what sockets were needed to remove the TB? I'm currently away at college and left my deep socket set at home... If I recall correctly, a deep socket was needed to remove the TB. Thanks!

AMDanBailer

Alright. I agree that you should look into cleaning the throttle body and see if that helps. In the meantime, give the Bama team a call and let them know what issue you're experiencing and see what they can do for you.

We can definitely make some adjustments to your tune and see if it benefits you in any way! Our Bama Performance tuning specialists are here in the building Monday-Friday from 9AM-5:30PM EST and Saturday 9AM-5:30PM EST. You can hit them up directly at 888.226.9764 and they'll get you squared away!

-Dan

6bangr

The Throttle Body requires a long 10mm socket for the bottom nuts, and a 8mm socket for the top bolts. I believe you torque them to 89in/lbs when putting it back on.

Eric052492

Thanks for the advice. Would you guys recommend against reusing the throttle body gasket and ring? I'd assume there is nothing wrong with reusing them as long as they are still in good shape.

- Eric

Delaware_Greg

Did you get gas from a station that you normally don't?

Was that station in the middle of getting a delivery?