MissMopar89

New to owning a ZJ, stupidly sold my XJ, ended up with about a hundred pickups and traded one of them since I missed the Jeep thing so much. I didn't realize what a different world it really is. I'm entirely ZJ retarded.
1998 ZJ limited 5.2 quadra trac non selectable 4x4. (slightly boring since I can't really go sideways anymore)

What I'm getting at is I'd like to learn as much as I can about them as soon as possible so I can take care of it, since it's so fancy and all. I'd just like to know things I should watch out for, things I should check on, etc.

I have a misfire problem, in the 8th cylinder. The owner before me who I know fairly well, and I was told the compression is fine. He installed a new injector, and replaced the plugs and the wires... I went to check the plug again and it was covered in gummed up sticky oil. It doesn't smoke up, or burn oil, so I'm fairly convinced it's not a valve seal problem... All the other plugs looked like they had a lot of life left to go. Is this a typical issue?

I was told that the misfire could be causing a shake I seem to get only at very certain speeds, and only when ON the gas and or going uphill... I've already replaced both calipers, pads, rotors, cv axles, hubs, and all the tie rods. If it's not the misfire what might it be?

Thanks.. Sorry for the novel, I'd just like to keep it in good enough shape to be a daily and I'd like to NOT worry about highway driving.

country_boy454

I would check your plenum gasket. These are known for going bad and there are companys out there that make kits to replace the gasket and never have to worry about it again. Take the air hat off and open the butter fly to the TB and shine a light down there. If it looks all oily then your gasket is shot.

http://www.hughesengines.com/Index/p...p?partid=26190

Congrats on the 5.9. Not many of them left!

MissMopar89

Thanks! I'll do that as soon as the morning rolls around. Sadly, it was a typo. It's only a 5.2 =[ however there IS a 5.9 at my local haunt (junkyard) and I think I may score the motor and wiring harness out of it. Or just cheat and get one from a durango haha.

Also; anyone able to direct me to a page that might have my fuse panel layout? the diagram in the owners manual is 100% not the right one haha. its on the passenger kick panel. Both reverse lights are out, and I've replaced the bulbs and reset the message center, and I don't think it's the relay, the diagram shows where everything is supposed to be and then it's completely non existant.

E-Rok

could be a plenum gasket OR the spark plug wires could be routed incorrectly. theres a TSB out there on the proper way to route them.

also if you dont like the full time AWD, you can swap in a NP242 or a 231, id recommend a 242 for a DD ZJ

MissMopar89

I was planning on swapping t-cases. I've been told it doesn't actually change mpg. Not that I didn't expect 10 mpg to begin with. I'd just fully enjoy having a v8 in something that does just fine with a 6. Sideways. And it's always fun to see how far you can get without 4x4

E-Rok

yea you wont gain any MPG, but who buys a Jeep for fuel mileage? lol

but about your idle, look into the TSB to test your plenum gasket. its $30 for the new gasket along with new bolts for the pan and intake manifold, and also comes with a thermostat.

I replaced the gasket (although I found out it was good when I pull the manifold), also did the wire rerouting with all new ignition stuff, and my 5.2 still idles rough from time to time. seems to be pretty common for 5.2's

MissMopar89

She actually idles pretty great. The misfire seems to only be an issue with acceleration. Though I have noticed when rolling forward or coming to a slow rolling stop she shutters a bit, but I just chalked that up to it being awd

country_boy454

I just want to say that you can get a lot better mileage out of your 5.2. Mine currently gets 22-25 mpg. Still have the NP249 in it. Also are you sure its a misfire and not ping? Considering you said it happens under acceleration.

You wont need the wiring harness to putt he 5.9 in your ZJ. They have the same wiring harness. Just grab the block and do a bit of updating to it. Good time to add a small cam also!

MissMopar89

Well the check engine light is on and the code is a misfire in the 8th cylinder. And the plug was super disgusting .... sorry pic is up twice

E-Rok

there is no way you are getting 22-25mpg in a 5.2 ZJ, not a chance in hell.

taythegibs

dang, i have to say x2 on the plenum, thats what my plugs looked like on the 5.2 after a few miles and it had similar symptoms. Sounds like you got yourself a nice 5.9 though!

agreed...

country_boy454

Im glad you think it cant happen cause I dont have to go into detail. No its not some magic chip or snake oil either. If your vehicle is running more efficient than it doesnt have to work as hard. I get better mileage in my 5.2 than I do in my 4.0 ZJ. Average in my 4.0 is 18-20 mpg.

Now you wanna talk about a gas hog, my XJ is lucky to see 200 miles on one tank of gas.....

E-Rok

so everyone else gets mid teens in a ZJ yet you can magically get mid 20's? thats better MPG than my 2500, which I highly doubt is obtainable.

country_boy454

According to your sig your 2500 is a diesel, not gas. If it was gas its a lot heavier than a ZJ. More weight to move more power needed to move it more gas being used to make the power. Dont have to go into detail there. I know more than a handful of people getting better than mid teens with their ZJ. No I dont magically get mid 20s. Took some work to get there. Summer months are the best for mileage. Winter is here and the gas has more ethenol in it. My mileage goes down.

blackjack12982

MPG on a new 5.2 ZJ was 14-16 MPG. You're not getting what you claim. Either you only drive downhill, or you're miscalculating...