3.8 JK throttle body
Thread Starter
JK Enthusiast
Joined: Jan 2011
Posts: 406
Likes: 1
From: Newton, Ks
3.8 JK throttle body
I have 2007 jk 3.8. I have been fighting a pulse when I chop the throttle from cruising to come to a stop. It will do it around the 800-1200 rpms, and it will bounce about 200-250 rpms. If I can hold the throttle in that area it will continue but if it comes out of that range it will stop. Jeep runs fine cruising and at idle. I had a etc relearn done on it and it made no difference. I do not want to just replace the throttle body to see if it corrects it, dont want to just start throwing money at it. I would like to try a known good throttle body if anybody would have one and is willing to trust me with it, I would be willing to pay shipping here and back. Or does any body have any other ideas or things I could try? I do have a sprintex super charger on it and is the only mod done to it. Tuner can not find or see anything in the tune that could be causing the pulse. So any help would be appreciated.
JK Freak
Joined: May 2011
Posts: 665
Likes: 0
From: Pittsburgh, PA
Did you try taking it off an cleaning it? How many miles are on it? If you have a lot of miles an constantly run low RPM'S you will get a a good bit of build up on it an will need to be clean. Type in throttle body in a search and see what you find
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
Could be the injectors shutting off during the deceleration, then coming back on when the rpm gets to a certain low point.
I can feel that with mine.
Could also be the torque converter unlocking, That would cause a jump in rpm.
If one of the above is what you are getting, there's no need for further troubleshooting.
You say the Sprintex is the only mod, but that's a huge one. Between that and the program to manage it, the fuel management may or may not include shutting off the injectors during deceleration. Maybe a call to Sprintex would shed some light on this.
I can feel that with mine.
Could also be the torque converter unlocking, That would cause a jump in rpm.
If one of the above is what you are getting, there's no need for further troubleshooting.
You say the Sprintex is the only mod, but that's a huge one. Between that and the program to manage it, the fuel management may or may not include shutting off the injectors during deceleration. Maybe a call to Sprintex would shed some light on this.
Last edited by ronjenx; Sep 22, 2013 at 11:49 AM.
Thread Starter
JK Enthusiast
Joined: Jan 2011
Posts: 406
Likes: 1
From: Newton, Ks
Already cleaned the throttle body, it was not to bad actually. ronjenx, I know the sprintex is a big mod but just stated that as I have not done anything to exhaust or the throttle body just for information wise. You say you feel it on yours but does it actually rev up and down, you can feel it also and hear it, super charger winds up and down. I have been in contact with the tuner and he is at a loss also as he does not see anything in the tune that would be causing it.