Hi everyone, this is my first post. I have a 95 XJ6 with 125k that is currently misfiring horribly.
This all started with a valve cover gasket change because the spark plug holes were filling with oil, so I ordered the gasket and changed it and the spark plugs while I was there, everything seemed to go smoothly until I started it back up and it ran horrible, very depressing.

My first reaction was that all that oil had gotten into the cylinders and it would burn it out so I went for a drive. After about 10mins of driving and it didn't get any better I was pretty convinced that was not the issue so I parked it and popped the hood to see the downpipe catalysts glowing red hot.

I assumed the were plugged up and had them hollowed out so I could get to work the next day. $245 later I have the exact same issue. I checked the coils by unplugging them with the car running, the rear 2(Cylinders 5 and 6) made no difference plugged in or not. I swapped coils 5 and 6 with the ones that were on 1 and 2, same thing. I optimistically changed the plugs again, same thing so it must be fuel right?

I replaced the injectors, same thing. I'm not getting a check engine light but my reader shows code p1313, misfire in bank 1. I also checked the connections on the ECU since I know they're prone to filling with water, but they appeared fine. I'm not getting any mechanical racket either. I am so lost and I really need my car, any help is greatly appreciated.

 

Hopefully some of the gurus can help

 

To clarify, "...same thing..." means the #5 and #6 cylinders were still dead after you swapped coils?

The wiring and connectors look OK?

Given the sequence of events I'd go back and examine everything I touched during the cam cover gasket replacement. Perhaps something was inadvertantly damaged during the course of the other work?

(No insult intended.....it happens to everybody)

Cheers
DD

 

correct, 5 and 6 were still dead after switching the coils and the connections appear fine. I've considered pulling the cam cover back off but would I have to replace the gaskets again? Well I suppose even if I do thats the least of my worries right. Any idea what things to check for if I take it back apart?

 

As I recall, the 5 and 6 coil primary wires are dressed in a way that makes it easy to swap them. I THINK I remember #6 having a yellow tape on it for ID. Maybe you should check what's wired where. Or maybe I've just lost my mind and can't remember correctly.

 

Thats what I was thinking.

 

Me too. The first thing I thought was ' The coils were swapped'
The first 4 coil connectors are routed so no mistake can be made but the last 2 ??????

I have seen it before.

bob gauff

 

you my friend are a genius, turns out that was the problem. Thank you so much everyone, she runs perfect now. Also just thought I would mention that even with the catalysts hollowed out I'm not getting any fault codes, and she seems a lot more peppy

 

just thought i would do a follow up on this, removing the cats WILL result in a fault code on this car, although the check engine (mil) light does not come on while driving, only if you turn the key on without starting it or check it with a code reader so obviously the car is not that concerned about it. anyway the code im getting is catalyst operating below efficiency threshold bank 1 and bank 2 and i must say other than this i have not seen any other negative side affects from removing these. im off to get some spark plug anti foulers to see if i can trick it and will post back when im done.

 

I have a 97xj6, how do you hollow out the cat?

thanx

 

well you drop the downpipe and ram a large metal rod through it, although I would strongly recommend not doing that unless you have no other choice