Topic: TJ Problems. Bogging, Bucking, and High Idle.

[lax22]

Hey guys,

I am having a slight problem with my jeep. For about a month or so now when i start it up after its been sitting it idles up around 2000 rpms and sometimes i have to turn it off and then back on to get it back down. Then when you start driving it bogs down at low RPMs as you accelerate and sometimes it bucks. So i figured it needed a tune up so my brother and I gave it one yetserday. For awhile it was good and this morning its doing the same thing again. High idle, bogging, and bucking. While i am sitting at a traffic light the idle would be normal and then jump up and then settle half way down and just continue being really inconsistent. While driving i felt like i was pulling an anchor and it had very poor acceleration. I cant see to figure out whats wrong with this thing. After doing the tune up yesterday it was running great so i dont think we did anything wrong there. I feel like a sensor is bad or on its way out. I was researching and think its either the IAC sensor on the TB or the crank sensor but i want to be sure before i go spending money. If you guys could help that would be great. Thanks in advance!

[Tsd]

Have you tried getting the error codes?

http://4bangerjp.com/forums/index.php?topic=3419.0

If nothing appears you could get the computer scanned by a OBD II scanner.
I have a busted o2 sensor and have problems with the idle too and acceleration and it tends to stall at low rpms.

Hope it helps 

Thomas

[lax22]

Thats the biggest annoyance is that its not throwing any codes. I tried to do the odometer thing but could not get it to show any codes. I guess i will run by autozone and have them scan it just to see if anything comes up. Been looking around the internet. seems like there is a big issue with the TPS and IAC sensors. Lots of people say buy mopar for these and not autozone or advanced. Looks like the dealer wants alot for these though.

[Tsd]

Mine has the check engine light on, but didnīt threw any codes through the odometer either.

Check for the o2 sensors coming up on ebay they are arround 30$ new. Crank sensors are arround 50$. I donīt know how much are sensors through dealerships there, but here they want to charge me 200$ for the o2  .

[Bounty Hunter]

I'm guessing throttle pos. sensor, but get it scanned.

Along with the tuneup, consider removing the throttle body, removing the sensors, and giving it a good bench cleaning.

[lax22]

Yeah I will have to dissasemble everything this weekend and give it all a good cleaning to see if that helps. I was trying to hold out for the 4.0 throttle body but until this mess is figured out i need to save the cash just in case some sensors are needed. Anyone have good experience with autozone and advanced auto parts TPS, IAC, and O2 sensors for jeeps? I hate shopping at those places but it sure beats 100-200 dollars at the dealer.

[TrailsLessTaken]

I've always used Napa to get all my parts from.  I just bought a new Bosch O2 sensor for my jeep last week and it was 42 with tax. The tps sensor is $38 and the IAC is about $67.  If you get me the year on your jeep i can pull up the part numbers and pricing for you

[lax22]

Hey there,

Just sent you a PM.

[TrailsLessTaken]

Hey there,

Just sent you a PM.

I just sent you the info, hope that helps you out

[lax22]

Thanks! It sure will!

[lax22]

Going to try and do the TPS today and post my results. Any suggestions for an easy swap?

[oldjeep]

Going to try and do the TPS today and post my results. Any suggestions for an easy swap?

Make sure you've got a good accurate voltmeter you you can get it adjusted properly. 

[chrisfranklin]

I've got a problem where I give the engine gas off of idle and it'll be slow to build RPM until it gets higher in the rev range.  Its a problem even after the Engine warms up.  Not showing any codes; the sensors are all going on 15 years old so I may pull them and clean them and/or replace them if its cost effective.

[lax22]

Got the TPS Installed and figured i would give it a few days before posting my results in case something went wrong. So far the the new TPS has seemed to solve my problems and things are more back to normal. I also cleaned the hell out of the throttle body and IAC housing. I took the IAC out and cleaned it with a paper towel sprayed with TB cleaner. There was a good deal of carbon in there as well so its hard to say if the new TPS solved the problem or if the cleaning did. either way its alot better.

Make sure you've got a good accurate voltmeter you you can get it adjusted properly. 

Just curious. How would i know if the TPS is not adjusted correctly and how do you go about adjusting it?

[smokey stover]

Hey there all, i am having somewhat the same problem with my 01 4banger, the major difference is that the idle settles down to normal at a full stop.  but until it is stopped completely it is up to 1800-2000 rpm.  i changed the o2 sensor a year ago and it fixed it for about 6 months.  i took it to a local shop and they changed both o2 sensors, now 6 months later the same thing.   i'm sure if i change the o2 it will work again, but what can be causing the o2 to go bad.  obdII code 0170, odometer codes it is either a "605" or "bus" followed by a 60 and a 68, then it says panel open.  also i have changed the tps the other day and no joy! any help would be appreciated.

TIA
Smokey