Check engine light/ cylinder misfire

Alright guys.....I am at a loss here. About 2 months ago, I had an issue. My radiator cracked when I was about 30 miles from home. Attempted to limp it home adding water constantly til I was about 10 miles from home. Where it decided to just quit. Got a buddy to pull me back to his place where we replaced the radiator. Right after doing this...I replaced all fluids, spark plugs, and valve cover gasket. Started throwing cylinders 2 and 3 misfire. Had a buddy check compression and 2 and 3 were low. So we replaced the head gasket, and again all fluids, filters, plugs, etc. Well, right as we got everything put back together, my water pump started leaking. Replaced that. Intemittenly after that the check engine light would come on and it would idle like shit. When it would go off, it ran smooth and strong. Well, i decided to replace the coil pack. Still no difference. Off and on. Well, a buddy told me about TSB 18-031-03 (Rough Engine Idle after restart following a Hot Soak). This seamed to explain my problem exactly. It would start to idle rough after a longer drive at highway speeds. So, I bough the heat shields and put them on injectors 2 and 3. This has been a week or so since they have been on and still no change, except the check engine light has bee on for about 1 1/2 weeks. Also, a few days before the heat shields went on, I Seafoamed the engine. i have no idea what is going on or wha the problem could be. Sorry fo the lengthy write up but I wanted t give as much detail and history as I could. Thanks guys.:smsoap:

What kinda Jeep ? What year ? What engine ?

What check engine light codes ? Your Jeep is trying to tell you what is wrong.

It's a 2000 XJ with 4.0 liter. Is there any thing I've missed?

My 2000 TJ would get the heat soak thing quite a bit, with a Cyl 3 misfire code thrown every time. It always went away, and I just learned to ignore it. It only happened while wheeling on hot days, and always cleared up after a couple minutes on restart.

Well mine hasn't cleared. It's been on constantly for 1 1/2 weeks. It used to be only for a couple days. I don't know what else it could be.

Did you do another compression test after replacing the head gasket?

The 2001 has an 0331 head that is well know for cracks in the head, even with out overheating like you did with the blown radiator. I was told yesterday that the 0331 head was also in 1999-2000 XJs. So it sounds like you should have replaced the head!!

And just like that. Drive 45 mins.... Turned it off...about 30 mins later turned it back on and the light is off and it's running good.

Small hair line cracks in the head will do that. The coolant is self sealing up to a point, and the cracks grow and shrink with thermal cycling. We drove my son's Ford Taurus for a year with a bunch of hairline cracks till they got worse and the valve seals on the bad cylinder went out. But we added sealer to the coolant, Bars Leaks sealers to stretch the time out.

Thanks guys.....I was wondering if it may be the head. Anyone recommend a new head that wont completely break the bank?

Replacing the head for an unknown Check Engine Light is rather extreme. The light could have been on for any number of simple reasons that are not fatal.

Compression testing, leak down testing,and observation of the oil and coolant for contamination, should be your first steps. Look into the oil fill cap with a bright flashlight, most often the 0331 head crack can be seen with the naked eye.

OP had low compression on the #2 & #3 cylinders before they changed head gasket. I asked if they rechecked compression since replacing the head gasket, but the OP did not answer. I agree, re run the tests, check for swapped spark plug wires, and the usual stuff.

But if it is still throwing codes for the same two cylinders that had low compression, the 0331 head is the usual suspect, unless he has bad rings, and walls????

I did not recheck compression. Should have but didn't think of that. Def gonna do that. Just so damn frustrated at this point. It's not swapped plug wires as its a '00 and has the coil pack. No wires to swap.

bet it's a head