Interesting new problem, rear end maybe?

[TwoOne]

I was driving the wife to work this morning, and of course it's like zero degrees out but I let the Jeep warm up before we left, well on the way there around 50 when I would let off the gas and let it coast down to about 45 I would start getting this chug and it felt like the rear end was dragging a little bit, I can't tell if it's a bad drum or a little bit of backfire. I seafoamed the gas this past weekend and it's been making it run a little rich so I don't know if that's what the issue is or it's some new problem developing, any ideas?

[XJH-007]

Define "chug"


I do that at the Pub.

[TwoOne]

Well, it's not so much a chug now that i've driven it more as it is a lurch, it feels like when I let off the gas and it's coasting that it is backfiring or something and start to lurch really bad. I seafoamed and it definitely has a leak in the exhaust manifold and it sounds like it's got either sucking or hissing sound coming from the same area.

Would a shot exhaust manifold make you run really rich and lurch like that due to a loss in backpressure or is it the bottom of the intake manifold that's hissing so bad?

All I know is it smells like its running extremely rich and it's leaking air / exhaust somewhere on the drivers side of the engine, hopefully you guys can help me nail this down so I can go get a new part and get her back to normal.

[TwoOne]

Another question I might add, if it IS indeed my intake manifold that has a huge vacuum leak and is dumping fuel to make up for it, which is what ive heard from someone else... Can the '00 intake manifold swap be done on an 88 engine?

[XJH-007]

Originally Posted by TwoOne

Another question I might add, if it IS indeed my intake manifold that has a huge vacuum leak and is dumping fuel to make up for it, which is what ive heard from someone else... Can the '00 intake manifold swap be done on an 88 engine?

Whatever the problem is...get the leak fixed first. Yes, a massive leak could cause a false reading on your O2 sensor...confusing it......

Intake manifolds from the newer XJ's will bolt to your 88 head...but the problem will then be your Throttle Body won't bolt right up and there could be other small things that would need tweaked.

Any year up to 97 should direct bolt, and the same with your exhaust manifold.