Baystate Jeepers

I'm inclined to go with the TPS first since it has the same behavior with or without the CEL.

I replaced the plugs and rotors. This didn't change the sputtering or power cutting out, but after a week, that symptom has gone away. I purchased and attempted to install a front O2 sensor, but the old sensor is stubborn and wouldn't come out. I still need to get a torch and get that sucker out. The code reader now also reads that the rear sensor is also reading incorrectly and possibly needs replacing as well. I'm not surprised by this.

Today, the day before I was about to tear into the TJ to do a bunch of lingering projects, the XJ once again started overheating. I was on my way out to get lunch and it got hot....again. Let it sit a couple minutes and then the gauge read just a hair over normal, drove it back the direction of work and got some fast food. Made it back to the office without the gauge reading hot, shut it down and smelled coolant. Its leaking out of the engine below the exhaust manifold. That's a sign of a back head gasket right? Awesome. Add that to the list of stuff I don't want to do. I've been chasing the cooling issues since the purchase of this XJ, the last thing I can think of to replace is the radiator. I haven't touched this one and the amount of crap that was blown out of the heater core is likely blocking most of the cooling capacity of the radiator as well. At this point, it needs to be swapped.

TL:DR
Known Issues:
O2 Sensors (front and rear) are bad, need replacing
Overheating

Previously fixed issues:
New Water Pump
New Lower Radiator Hose
New Coolant Temp sensor
"Flush and fill with new coolant" (in quotes as the it never looked like fresh coolant)

Assumed fixes:
New O2 sensors
New Head Gasket

Possible fixes:
New Radiator (the only item i can think of in the coolant system that hasn't been checked/replaced)

Update: Because I a man with a one track mind, I went out to the jeep to check the fluid levels. Overflow container, full. Opened the radiator cap....sludge. Hmmm... thats no good. Clearly, the cooling system is full of contaminants, radiator is likely plugged which likely caused overheating conditions which likely caused the head gasket failure. Beautiful. I guess I won't be working on the TJ this week.

Anyone else have thoughts?

Clogged cat could of been causing all of this if it still has them. Sludge could be oil, gas what not all mixing together depending where and how the gasket leaked or head cracked.

Cherokee is down again. I'm not spending more money on it. It's a good body, good transmission and transfer case. Diffs are unknown as I never got around to doing a gear oil change. It's a solid Cherokee other then the whole engine thing. It's on Craigslist. If you want it, PM me and we'll work out a deal.

So yeah TJ needs some attention. The lower control arms need to be rebuilt and a few other things need to be repair/maintained. To pass inspection, the tailpipe needs to be extended out behind the body, and I need to solve a check engine light. My reader is showing P2098 Post Catalyst Fuel Trim System too lean Bank 2. I did some looking and apparently there is a TSB for it. Do I just take it to the dealer to have them service that? I guess they need to rewrite the PCM to solve that.

if its a PCM rewrite then you will have to go to the dealer. I dont know NH inspection laws to comment further.

pirahnah3 wrote:if its a PCM rewrite then you will have to go to the dealer. I dont know NH inspection laws to comment further.

Ah, thanks, I thought as much. I haven't ever taken a vehicle to the dealer to have it serviced.

For inspection, the light needs to be off and all inspection readiness sensors satisfied. Just need to extend the exhaust and fix the light and the rest of the jeep should be good to go for inspection.

There are places that will do a PCM rewrite for you and even tune them further but considering its a jeep and not looking for huge performance gains I dont see the neccesity to do such. That and the cost of that is quite high for what you will get out of it. The dealer SHOULD do it for free if there is a valid TSB for your vehicle. Check online for info about it and ensure that you are armed with some info on that TSB and dont be afraid to push back and make the service department go hunting for it.

Chasing issues update:

Wrangler is finally state inspected. The process with the dealer has re-instilled my dislike for dealerships. I took it to them for the check engine light, their normal process for that light is to pressure test the exhaust. They found a "crack" in the front cat, so stopped their process and called to estimate the replacement at $2k. I said i'd be by to pick up my keys. I then took it to Lou's Custom exhaust who welded a couple tiny holes, took 5 minutes, cost $40. Exhaust was fixed, but the light remained. Ended up getting two rear o2 sensors at sullivan tire when the jeep decided to overheat. New radiator and o2 sensors and the light stayed off for a week. Got the official sticker saturday, and the light came back on sunday. Similar but different code. I'll deal with that in 10 months.

Cherokee hasn't sold. No surprise there. I was speaking with a friend about the overheating issues, and when i mentioned that it hisses after being shut off, and that its coming from somewhere below the manifolds, he immediately went to freeze plugs. I crawled under it yesterday and it does appear that there is a hole in the plug right next to the engine mount. If that's all it is this time, I believe I can fix that! Has anyone ever used the rubber freeze plugs? Basically a rubber puck you insert, then tighten down a nut that squashes the rubber sealing the hole. My question is this, are these better or worse then the OEM Metal plugs? install isn't that much harder, but I would think that the rubber could seal better. Thoughts?

If I get around to this project soon, and it works, I'd have to throw an exhaust in it, then it could pass inspection and be back on the road. I'm debating not throwing any more money into it, or just getting it done.