BstrdXJ

I'm having engine hiccups at highway speeds only. It only happens when I'm constantly on the gas pedal. If I'm accelerating hard it doesn't hiccup, and if I'm coasting it doesn't either.

Occasionally my engine will just stall and die. It's usually when I'm slowing down, turning, or shifting from park to reverse or something similar.

My 4wd (any gear) will sometimes engage, and then come out and clunk, or not engage at all and just clunk.

I have an 89, with a 93 HO I6. I have the AW4 tranny and the NP-242 t-case.

I feel as if the hiccups are a crank sensor problem, the stalling and such is a vacuum leak and the 4wd issue.. I haven't the slightest clue what it might be. I'd just like some better guesses or something before I start throwing parts at it. Thanks!

Other issues that might help, on a steep inline or high acceleration, my fuel gauge moves heavily to one end or the other. My oil pressure is spiked to the high end at all times (although I'm sure that's just a bad sending unit).

Turbo X_J

What are the codes?

BstrdXJ

No check engine light (might not even be hooked up), and I have no idea where the OBD-1 plug is located at, if the guy who threw the engine even put that on. I've looked under the hood, and there's a giant mess of wires near the pedals that I've sort of looked at.

Engine installation was done by a pretty ratty backyard mechanic.

Turbo X_J

"Engine installation was done by a pretty ratty backyard mechanic."
May be rather difficult to accurately diagnose.

BstrdXJ

Yeah, unfortunately. I feel as if throwing parts at it might be the only option I've got, aside from going to a shop and paying outrageous labor rates.

1976Mustang

The stock Chrysler computers OBD-1 plugin is right next to the computer in the engine bay (Crammed between the computer, airbox, and brake cylinder assembly) If he swapped in an HO engine I can only assume he swapped in an HO computer too.

belvedere

They could both be caused by a vacuum leak.

BstrdXJ

This is what I see. I feel as if I'm missing a component or two.

1976Mustang

Hmm, I don't know jackcrap about Renix era XJ's. Someone get Cruiser!

BstrdXJ

Well, it's a 93 HO.. in an 89 chassis.

1976Mustang

'89 is Renix, I can tell from the way the engine bay is set up (And that is the limit to what I know about Renix lol). I guess he used the Renix ECU, but IDK where it's mounted or anything. We need one of the Renix gods to respond.

OleBlue

The obd plug for a renix is by the relays on the passenger side of the engine bay.

Try doing a simple tune up, that hesitation sounds exactly like mine when i had a fouled plug. plugs/wires/cap/rotor.

Im guessing the guys that put the ho motor in didnt swap the computers, its easy to just swap a later model engine into a renix era by reusing renix intake gaskets, and all the renix intake/manifold etc.

As for the 4wd, try adjusting your shift linkage, im not an expert on the 242 but maybe the "differential" inside of it is going bad. If the problem keeps happening just remove the front drive shaft as to avoid further damage.

The stalling may be from a bad egr valve.

Dont expect to get any codes from a parts store, none that i have found carry the expensive obd1 reader.

BstrdXJ

I have an OBD1 reader at my disposal, I'll poke around the engine bay and see if I can find the plug, and check everything else out.