Can you pull a used working coil pack from a JY or just get one from the parts store and slap in on to see if that fixes the issue. These sould like the symptoms a mechanic described to me when his coil pack went bad. Otherwise check your TPS. When mine when bad all kinds of wierd things happened to my engine. Slight bucking at highway speeds, missing and stumbling at cold start ups and loss in power.

 

He already changed the coil pack..

 

oops, sorry, thought I read through all the post, I missed that one.

 

just ran a diagnostic came up with a tps code so i changed that and the truck ran good for 2 minuets before it threw up 2 more codes an iac and misfire 2....im completely stumped

 

Get some throttle body cleaner and see if you can just clean up the IAC. I dont know if a bad IAC could cause a misfire but thats what I would start with.

 

whats your oil pressure running at, at a idle?

 

at idle im at 35lbs and i guess ill give the throttle body a cleaning tommarow...i still thin this is verry weird....

 

any other imput???? thankyou

 

Fix what ever causes any codes being thrown first.I know on some vehicles you need to clear old codes after repairs are made.

If you get all the codes cleared and they stay gone the next thing I would look at is fuel delivery if there are no obvious causes to your symptoms.
With all of the discussions leading to a cracked head or blown head gasket I would look at that as well.

 

im not getting coolant in the oil and its not overheating

 

1. Clean both the throttle body and the idle air control. Regardless of whether this fixes your problem, it is good maintenance. More on that below.

2. You have an engine that has a suspect cylinder head. The "infamous" 0331. The #1 symptom of a cracked 0331 head is "unexplained coolant loss". So are you using coolant? That can lead to a misfire condition on the 00-01.
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The Idle Air Control (IAC) is mounted on the back of the throttle body. The valve controls the idle speed of the engine by controlling the amount of air flowing through the air control passage. It consists of a stepper motor that moves a pintle shaped plunger in and out of the air control passage. When the valve plunger is moved in, the air control passage flows more air which raises the idle speed. When the valve plunger is moved out, the air control passage flows less air which lowers the idle speed. Over time and miles, the IAC can get carboned up which can have an adverse affect on idle quality. Cleaning the IAC may restore proper function and is an easy procedure to perform and good preventive maintenance so it is never a bad idea.

CLEANING THE JEEP 4.0 IDLE AIR CONTROL

Remove the air filter cover, associated hoses and the rubber boot that goes from the air filter cover to the throttle body. Remove the IAC with a torx driver (2 bolts; one can be kind of hard to get to)

“Gently” wiggle out the IAC from the throttle body. Gasket on the IAC can be re-used if it is not damaged

Clean the IAC with a spray can of throttle body cleaner; inexpensive and available at any place that sells auto parts. Throttle body cleaner is recommended rather than carburetor cleaner as it is less harsh, safe for throttle body coatings and is best for this task. Use cleaner, a rag and a toothbrush and or Q-Tips. Be gentle; don’t twist or pull on the pintle that protrudes from the IAC as it is fragile and you could damage it.

Thoroughly spray clean and flush where the IAC seats in the throttle body with the same spray cleaner

It is also a good idea to clean the entire throttle body itself, the butterfly valve inside of the throttle body and all associated linkage as long as you have things disassembled

Reinstall IAC and check idle quality

 

Mine used to do the same, I fixed it by clearing the ECU so it was using the factory map not its learned one, made a big difference. I also went through and cleaned and replaced sensors and pt a new ground wire from the battery to the body.

 

That does not mean that your head gasket isn't blown or that your head is not cracked.
You never did post what the old plugs looked like when you pulled them,you just said you replaced them.Or did I miss it?sorry if I did.

 

all plugs where fine except #2 which was black(carbon coated) and it wiped right off, i have 175 across the board in cylinder pressure, still getting fuel in all cylinders,the xjs been down for almost 2 months now and i need it soon bc spring/summer and beach time is coming

 

Anyone??? Beach is finally open and I can't go on it