Newbie that needs so help!!!

Hello all,

This is my first post here, but I have been lurking around reading and searching a lot of posts about a problem that I have!! I have found so useful fixes but none have worked so far!!!!

I just recently bought a stone white 2001 xj with 81,000 miles on it. The truck is a 4.0 with an automatic. This is my very first jeep and so far I am not happy

When I bought the truck on the 5th of January it ran like a champ other than a little ehxaust leak on the manifold! Anyway I put some sea-foam in the tank and through the brake booster hose and on the 13th I went to a concert and upon getting on the freeway I start to get up to 70 m.p.h. and at about 60 it starts stuttering between 3,000 and 2,700 r.p.m. then if I let off the go- pedal and gradually get back in it it will get up to speed no problem. When I got off the freeway this thing was idling like crap. When I accelerated again it started stuttering at 45. So after the concert was done I when home experiencing the same symptoms.

The next day I put a scanner on it and it pull one code P0303 cylinder #3 mis-fire so I figured I would put some plugs in it. The plugs I pulled out looked good (champions) except for #3 cylinder that one was loaded with gas and looked like it has not fired in a while. I replaced the plugs with the recommended NGK ones that I gapped to .035 and I start it up and it is still doing the same thing. So I start searching on this site for P0303 possible problems and I have found people with minor issues and people with majors issues with their jeeps. I found the TSB for the injector heat shield sleeve so I go to the dealer and pick one up get home and install it and it doesn’t do anything ( I really did not expect it to fix anything when I saw what it was). Next I decide to replace the coil but again nothing happens so I decide to get a good scanner on it and during the injector test the #3 injector is hanging open (the sea-foam probably knocked something loose) so I figure that’s it. I take the coil and plugs back out and #3 is soaked with gas! I check all the gaps and swap #3 plug with #4 evacuating the cylinders before putting the plugs in. slap a little di-electric grease on the plugs and put the coil back in. I then proceed to pull the fuel rail to change that injector. upon putting new lower o-rings on the lower end of the injectors I put the injector in with the heat shield. I go to start it and the symptoms still exist even after I have cleared the code.

So now I am stumped so I take the throttle body off the intake a proceed to clean it with throttle body cleaner, also I removed the IAC and cleaned that really well put it all back together and it still runs like crap!!!

WHAT DO I DO NEXT?

I have not done any vacuum, cylinder, or cooling system tests, Also my jeep was built in June of 2000 and I saw a TSB for updated software for xj built prior to April 2001 but I can’t see this making a difference if it was running fine before!!! I did lose a little bit of coolant but not much maybe a ½” out of the recovery tank and there is milky crud on the bottom of the oil crap but that could be condensation. I know the 0331 head is prone to cracking between #3 and #4 but I really hope this is not an issue. I don’t think I overheated the truck but I don’t know the jeep runs at 210 degrees and has since I bought it so I don’t know if that’s normal or not !!!

Any help would be greatly appreciated, and sorry for the long post!!!! HAHA

Later,

DEVLYN

Hallo. I would be carefull with the use of sea-foam for the Oxygen sensor.:rtm:

p.s. My '92 is running 210 F. in the summer.

I run seafoam often with no ill effects. Doubt it is the seafoam that caused th problem!! I am not sure of the cause of this problem, have not read much on it. Good luck!!

You've done a lot of the usual stuff to try to isolate. If it were mine, I would definitely start testing. The milky residue could indicate a head gasket or head problem. Compression test data is never a bad idea, especially if you have a suspect cylinder. Cooling system pressure testing and cylinder leakdown tests also come to mind. I think testing may very well tell the story here....

BTW, 210 is the normal operating temp for your XJ

You can actually look down inside the valve cover with the filler cap off and look for any green tint in there. As for NGK's, I've tried them in a couple of vehicles and was not very happy with them. We've got 5 or 6 jeeps in the family and ALL of them run Champions with no problems. It sounds like your #3 is not firing, swap the coil between another two cylinder and see if that helps or changes. Compression test would be a good idea as would the test for the exhaust gases in the coolant. Another thing you might want to try is disconnect the battery for a half hour or so and let the ECU reset, then take it out for a drive for 30 minutes or so, the ECU will relearn. I've seen that clear up some problems including what I thought was a dead spot in my throttle control sensor.

i dont know how you can swap the coil on the coil pack set up. but if it was bad it should misfire on cyl 4 also since it shares the same coil. if you are losing coolant i would check for a milky trail between 3 & 4 rocker towers under the valve cover. sometimes on a #3 misfire the exhaust valves hang up in the guides, and there is a procedure for freeing them up, and a pcm reprogram may help. other times a valve job can resolve the problem. but if in fact the head is cracked it would need to be replaced and that would correct the problem.

jneary said:

i dont know how you can swap the coil on the coil pack set up. but if it was bad it should misfire on cyl 4 also since it shares the same coil. if you are losing coolant i would check for a milky trail between 3 & 4 rocker towers under the valve cover. sometimes on a #3 misfire the exhaust valves hang up in the guides, and there is a procedure for freeing them up, and a pcm reprogram may help. other times a valve job can resolve the problem. but if in fact the head is cracked it would need to be replaced and that would correct the problem.

Click to expand...

I've never looked at the coil on rail setup, wonder if the connector on the #3 could be bad.

I would suspect a faulty injector. Swap to a different cylinder and see if the problem tracks.
While you are at it, do a compression check.

Welcome to the 0331 head misery club. Watch on craigslist. I just picked up a 0630 head out in Waterford for $50. The milky residue under the oil cap convinced me. 2000 XJ - and I thought it was so great to get one of the later years.

Thanks all,

I will start doing some tests and I will let you know the results!!!

Later,

DEVLYN

Hey guys,

I took the valve cover off and the head is cracked between #3 and 4 cylinder, Thanks for all the help I really appreciate it so now I need to get a head

thanks again,

DEVLYN