OEJ

sorry i didn't realize you were in calli. so i guess you can't use high flow cat and the down pipe without the precat????

that sucks.

askingxforxit

Thats right, I'm pretty much screwed. New oem sensors are on order at the stealership, really hoping this solves the problem. And I might as well get the banks headers while I'm at it

OEJ

yead it should solve it. i mean i went through the same exact thing.
so please let me know if it worked.

askingxforxit

For sure, once I get them and test for a couple weeks I'll come back

askingxforxit

Ok I'm back. Brand new Mopar o2 sensors (all 4) and still the same problems. Multiple missfire on cylinders 4 and 5 this morning. I think I'm just going to jump right in to replacing the head as this xj had been overheated by the previous owner about 100,000 miles ago. I'll come back after the head is replaced but it's going to take a while to get the money and time.

OEJ

I don't recall if u mentioned the over heat issue, so that def could be it.
But maybe u should ohm out the coil packs first before condeming the head.

With the over heated issue I would think it would have shown its self well before 100k. Not to sure though. Def test the coil pack first. Wish I had noticed u had a 2000, I would had sugested that first. Sorry buddy.

askingxforxit

My mechanic buddy has also suggested getting a new coil rail and at only about $120 for a new one it's probably worth it.

Kalali

Coil rails rarely fail and your symptoms don't sound like a faulty coil pack. Your money your choice but if it were me I'd check local JY for used cats.

askingxforxit

JYs in california remove the cats before putting a vehicle in the yard.

OEJ

I completely disagree with this statement. No disrespect intended Kalali.

Coil packs can most def fail. Older stlye ignition systems with a distributor and a single coil have a longer life span than any coil pack or coil on ignition system i've seen.

You could also have a heat soak issue with on of the injectors. there was tsb issued for 00-01 cherokees for heat soak issues . you might want to see if you have any recalls of this nature.

Its a missfire code. meaning quite possibly that one or more the coils is not firing. I would listen to ur mech.

btw no jy will sell you a cat. Its a federal law that they can't. if they are its illegal in any state.

askingxforxit

I'm going to try new coil and spark plugs tomorrow. The rough idle and exhaust smell is intermittent which is leaving me to believe that it might not be the head. If a new coil doesn't fix thus I'm just going to get a rebuilt engine from ATK. If I'm going to spend hundreds on a new head plus install I might as well just get s fresh engine. I'll update you guys in a few days if the new coil works or not.

One thing I've learned about owning an xj, it's good to have a second car lol

askingxforxit

I'm not sure if it's heat soak related, I've been trying to avoid pulling the valve cover off. But it does have the heat shield installed. Still no coolant loss as far as I can tell in to the head, I did have a couple loose coolant hoses but thats neither here nor there.

OEJ

ok. good. if you have the shields then ur prolly good. even better that you haven't any coolant in ur oil.

askingxforxit

If it's not the head I'm going to assume coil or cats

bsmith97xj

Wouldn't a lean miss be injector/fuel related?? A bad coil/ spark plugs would leave it rich. Too bad you can't check your fuel trims in the pcm data.