Rough idle/stalling

[907_jeep]

missed you guys :D
been a very long time sence i have posted but i need help and more then 1 mind to help with this

first its a 90 limited xj 4d 4.0l i6 4x4

i have replaced the ccv tubes,greased and cleaned about every connection under the hood,replaced the cps sensor..and it still idles like crap and will stall out periodically in gear and reverse at lights if not in nuetral.. wth else could it be? iac? low fuel rail pressure?

[prerunner1982]

Clogged fuel filter...

I have had this problem on other vehicles (mainly my old Chevy pickup) where the filter would get dirty and idle like crap and stall out when at lights, but once you were on the gas it ran fine. When you are on the gas there is enough fuel pressure to push by the clogged filter, not as easy though at idle.

Just an idea, never had this problem on the XJ though...just going on previous/other experience.

[907_jeep]

i can fix this..were should i go from there if that isnt the case? clean tb and replace or clean iac?

[LizardRunner]

check the tps first. Then those would be next

[4.3LXJ]

In addition to the TPS, the Idle Air Controller is suspect. They get dirty and sticky. First try cleaning it. If it is dirty and sticky it cannot respond to changing conditions like being put into gear, AC etc.

[dagr8tim]

Clogged fuel filter...

I have had this problem on other vehicles (mainly my old Chevy pickup) where the filter would get dirty and idle like crap and stall out when at lights, but once you were on the gas it ran fine. When you are on the gas there is enough fuel pressure to push by the clogged filter, not as easy though at idle.

Just an idea, never had this problem on the XJ though...just going on previous/other experience.

I think you described the condition in my XJ. It's an intermittent idle drop and occasional stall. After reading this yesterday and thinking about it over night. Mine seems to act up when it's low on fuel (under 1/4 of a tank).

[907_jeep]

deff not gas issue.. and on the topic of tps..i has a new one in it about 6 months?? can i still be adjusted? or do i have to buy a new 1 again then do it?

[4.3LXJ]

Check your idle air controller first. It is the first place to start with rough idle.

[Weldmen]

Sounds like a vacuum leak to me. Get a can of carb spray, get it idling in park and spray a little shot around the top of the motor and vac lines and listen for the rpms to change. I had a similar problem and it was a vac line at the charcoal can on p side fire wall. I have a 95.
Good luck

[907_jeep]

charcoal can??? lol wtf is that

[4.3LXJ]

It is a filter hooked up to your gas tank vent to collect vapors on hot days. The engine siphons them off when running with engine vacuum

[907_jeep]

ok so new question on the manifold on my jeep there is a nipple with a hose to it ...wtf is it cuase my jeep idles waaaaaay better with it off? does it hook up to something and maybe i found my shitty idle problem

id follow the line but iam in alaska and with it being 10 outside it gets cold really fast

[4.3LXJ]

All you may be doing there is introducing a vacuum leak instead. Besides, if that hose goes somewhere, you need it.

[pvt.tadpolxj]

You can check your battery post's to make sure they are getting a good connection...Sometime's all look's good on the outside of battery post's, but the terminal's can have a corrosion on them and they need to be scrapped off a little to create a better current to all of your component's....

[caravelisland]

Had similar rough idle/stalling and also had to apply a little throttle to get it started. Replaced the battery (because it went dead) and it now runs great. In my case it appears that a weak battery, although functional, caused the idle problem.
-Stock 96 Cherokee Sport