I have a 2001 XJ, it has been running terrable for about 5 months. I have put over $1000 dollors into it and it has not changed the way it runs at all. It is giving off trans codes and cilinger 1 miss fire ( trans shifts fine)

cam position sensor and assembly
cat back exhust
spark plugs
coil packs
cilinder 1 fuel injector
computer


after all that I brought it to the Jeep dealer and they put a crank sensor, and oxygen sensor and checked and cleaned all the terminals before they told me they dont know what the problem is

if anyone has had this problem or has a guess any help would be great

 

Did anyone do a compression check to make sure all cylinders are up to par. With all you have replaced maybe it is mechanical and not electrical or a component. I hope you are not friends with the dealership,I will never understand how any shop or dealer could ever allow a veichle to leave there shop without repairing the car or at least knowing what the problem is. To replace a sensor at there cost is not cheap,i hope they did not charge you for there labor.

 

What is the problem, running badly is not a discription?

 

when it hits 3000rpm it kicks into limp mode (check engin light starts flashing and will not go any faster) the exhust also gets very hot at the tail pipe end, water will boil right off (put the cat and muffler on after this was found)


the compression test was good 150psi and up on all cilinders, my parents know the owners of the dealer and they said the spent over 20hrs trying to find the problem.

 

i have had this SAME problem before not on a jeep but on a straight six to the best of your knowlege has the head gasket been replaced if you get some side ways back yard mechanic that did it it could easily be your problem with my experience there was a piece of old head gasket between the the head and new gasket and was sucking cold air in but not blowing compression out(i have no clue how but its obviously possible) and it ended up burning up the side of the piston(i drove it for 2 years before it finally burned up enough to pump oil past) i reallly hope im wrong but its a possibility

 

Hot exhaust means lean mix, check fuel pressure.

 

fuel pressure ok

Ive had the jeep for 50K miles and I have never put anything mechaincal into it for 4 years until this

 

What do you mean did uou fix it or it wasn't the F press.?

 

it was not the fuel pressure

 

So what was/is it?

 

I dont know its not fixed

 

Map sensor?

 

i too had this same problem mine was reading a torque converter code and the catalytic converter code (that is what it means wen the light flashes it supposidly means sever damage to the cat) so i hacked mine off and put a hollow one on the it was still doing it so i took it to autozone they hooked it up and said cylinder 3 is missfiring so all i had to do was change my coil pack and plugs and i have not had this problem for well over 30K miles i would deff try this if i were u they can be pricey tho i think llike 200..so lomg story short i fixed my jeep and my dynomax cat back exhaust never sound better then it does now hope that the coil pack will fix your troubles

i was also told that if you did replace your coil packs it is very possible to get a bad one that is brand new

 

My 2001 at high rpm with head # 0331 had hair line crack #3 & 4 cylinder - It would get hot and run bad higher rpms - I replaced engine for knocking. Try checking for crack manifold and plugs for discolor. # 0331 heads are bad to crack after getting overheated.

 

I'll just throw this out there, how about weak vavle springs? can't keep up on high rpm. or chryslers tsb on exhaust valve rotation/carbon build up causing misfires? tsb#09-003-03