Bad Idle my xj trouble again

[99XJ]

Hi fellow Ajor.
i bought the xj 2 weeks ago and i have spent soooo much already until yesterday, i was cruising about 1 hour or so, when i just put the gear to D without accelerating the idle is reving until about 2000rpm and then down and go again and also on traffic light gear also in D and my foot in the brake the idle is up and down again it's like im changing the camshaft. I don't know where this came from does anyone can help me? i just fit new cat converter and did major service on this xj. what seems to be wrong?

cheers

[hillsjeep]

Have you got any error codes?

Try a search I've heard this symptom discussed numerous times before. Try with these threads for starters: http://www.ausjeepoffroad.com/forum/...d.php?t=65587&
http://www.ausjeepoffroad.com/forum/...d.php?t=62680&

[Rodgebone]

sounds like tps or dirty idle control valve....but pull codes first!

[99XJ]

I don't have error codes. How do you clean idle control valve? and would it be o2 sensors playing up? i hate this jeep

[hillsjeep]

Originally Posted by 99XJ

I don't have error codes. How do you clean idle control valve? and would it be o2 sensors playing up? i hate this jeep

Don't be too hard on the Jeep, you're just fixing up something the previous owner couldn't be bothered to fix. Once you've spent the money you'll have many years of fun Jeep'n ahead of you.

It could well be the 02 sensors. Try taking them out and soaking them in petrol and then give them a good clean with a tooth brush. It may not completely fix the problem but if it improves it, then it would be a sign they're too blame.

Sorry, don't know about the idle control valve though.

[Rodgebone]

ok, no codes....so clean the O2s as hills suggest (sounds like a lazy O2)...the tps isnt setting a code so discount that....cleaning the idle control: remove the throttle body and clean it thoroughly throughout the bore especially around the throttle plate (i prefer removing the throttle plate) w/throttle body cleaner...bolted to the side of the throttle body is a valve with a sensor screwed on the end of it (it would have had an electrical plug attached to it)...unbolt this valve from the throttle body and remove the sensor...soak it in throttle body cleaner for 30 min and then spray it out with fresh cleaner while moving the plunger inside up and down and also twisting it...put it back together...id also spray wd-40 around the intake manifold area to see if you have a vacuum leak somewhere (gasket, crack, broken hose etc...)