I recently replaced my head gasket on my 96 xj. Today i started it up and it has a misfire. No codes on the scan tool. I know my fuel rail had some rust in it, could this be my problem? The misfire also got worse after i did a WOT run on my street. I don't know what it is. I know my temp sensor at the back of the head isnt connected. I was also wondering which temp sensor turns on the aux fan. The one on the thermostat housing or the one on the head? Thank you.

 

Id say its the head gasket mine had the exact same symptoms and i pulled my head last week to find a blown gasket between 3 and 4

 

And i posted that ^ on the wrong thread

 

"Today i started it up and it has a misfire."

If the fuel system is full of crap that's a possibility but first check the firing order.

 

Firing order is correct

 

did you replace the head bolts? check compression, pull plugs and look for antifreeze

 

Head bolts were replaced. Im starting to think its something deeper in the motor. It knocks on cylinder five after it leans out. Im done with this motor for awhile. I might put my neighbors 0630 head that he has on the jeep and see if that fixes anything.

 

Hows the fuel pressure? Mine had a knock at idle and a bit of a misfire, sounded like lifters,... "lean misfire", bad thing for the top end. Fix was new fp.

 

Ill check this week. Maybe it had a lean misfire and caused the HG to blow again?
Either way im getting a spare motor

 

or maybe you just need a fuel pump

 

Lets start from the beginning, why?

 

I replaced the head gasket because it was running rough and had low compression on two adjacent cylinders.

 

Cylinder head/engine block cracked?

 

No head and block are fine. The motor has 250k on it so its about time it starts falling apart 😂

 

sorry dude I'm outta here.