Jeep Cherokee Talk banner

1 - 14 of 14 Posts

·
Banned
Joined
·
27 Posts
Discussion Starter #1
Hi everyone! Glad to be a part of the site.

Just got a 2000 Jeep cherokee. It has the 4.0 Inline six.

It is not throwing any codes at me, but it is misfiring. It's running really rough at idle and the MPG's are in the toilet.

Here's what I've done to try and remedy it-

Spark plugs, Sent all 6 injectors out for cleaning-all100%, cleaned the fuel rail, new air filter, oil lube and filter, Checked compression, pulled the valve cover to check the rockers and stem movement.

I'm not familiar with this coil pack. Nothing that I throw at it seems to help.

Any help would be tremendously appreciated. Thanks!!
 

·
Registered
Joined
·
26 Posts
Interesting problem. I only say that because my Cherokee 2000 has been rough idling since Monday. Today was the first day that it seems to be idling better. I chalked it up to maybe getting some dirty gas (filled up where I don't usually get fuel). I added some gas line antifreeze because of where we're located (Alberta). It stalled out twice on Monday. Yesterday, the rpm dropped to less than 200; was going to stall, but it raced up to 1000 rpm and seemed to settle down. The 4.0L is still a baby. The engine only had 10 000 miles on it when I got it and it will be 2 years old next month. Not sure if this helps you, but I'm curious to follow how things turn out for you. It may give me some clues.

Will
 

·
Banned
Joined
·
27 Posts
Discussion Starter #4
Interesting. Its not that cold in Philadelphia, so nothing there. The gas? Don't know. It was in the tank when I bought the truck.

Im going to try and replace the TPS (throttle pos sensor) and the CPS
( crank positioning sensor).

Maybe these will have some effect on it. It Idles low and it sounds like a musclecar at the tailpipe so I know it's off. Any other ideas would be really helpful.
 

·
Registered
Joined
·
488 Posts
just wondering because mine does it once in awhile:brickwall: havent found away to fix it yet...hope i get some pointers out of this
 

·
Registered
Joined
·
444 Posts
its not the CPS.. it wont run at all when thats bad.. explain your "rough" idle.. does it chug chug chug wanna die or does it want to idle high then low then high all over the tach kinda idle or what..

if its all over the tach kinda idle its your idle air solenoid.. its the other plug on the throttle body that ISNT the TPS.. those get covered in carbon from the crankcase breather and wont seat properly.. just pull that out shoot some brake clean on it and wipe it off an stick it back in..

a lazy O2 sensor could cause a rough idle but that would throw a check engine light..

double check every single plug thoughout your engine compartment.. make sure everything that is suppose to be plugged in is plugged in..

hope this helps.. describe rough a little better and i could narrow it down better for ya
 

·
Banned
Joined
·
27 Posts
Discussion Starter #8
The rough idle is a chug-chug-chug. It reminds me of a 5.0 I had that was only running on 7 cylinders. Ran fine, but idled like crapola! It does not jump all over the tach. Stays pretty steady, but that chug-chug-chug-is really noticeable at the rear end of the jeep. The tailpipe.
 

·
Registered
Joined
·
444 Posts
whats it tachin' at the chug chug idle?? hows this throttle response, when you punch it does it try and die out or does it come right back to life?? mine when i first bought it wanted to idle at like.. 500.. the 4.0L should idle at around 900.. give or take 50..

there is an idle adjusting screw in the throttle body.. DO NOT TOUCH IT!!!!!! it will make your problems much much worse.. if it is tachin a lil low take some pliers and tweak the piece that comes up against that screw..

its kinda tough diagnosing through the internet lol.. hope this helps
 

·
Banned
Joined
·
27 Posts
Discussion Starter #12
Funny thing, Went to check the rpm's once I got her running again and NO GAGUES!! Only gague that works is the gas light, but there is gas in the tank. Any ideas now??
 

·
Registered
Joined
·
1 Posts
I have a 96 grand cherokee 4wd. Been a good one. Has been running and driving fine. Yesterday it started running hot needle was buried. Filled radiator with antifreeze, now isn't running hot, but sitting at a stop light in drive, bad vibration, but in park or driving down the road, nothing. Also, the more coolant I put in the radiator while jeep is running, the rougher it sounds. Any ideas???
 

·
Registered
Joined
·
24 Posts
After reading your post about a coil pack. Did you change the cap and Rotor if it has one?? What is your running temp? My temp sensor was taking a crap a caused a rough idle and hard warm start due to the CPU thinking the engine was cold when it,was warm changing mixtures
 
1 - 14 of 14 Posts
Top