xpsniper

Hello Everyone,

Bought a 2nd hand 96 XJ Sport, i6 4.0L Automatic not to long ago (previous owner ran it hard and took no care of it).

Just took it for a run in 4wd the other day, just on the beach so nothing hard. Parked it up at the camp site and it would turn over when i tried to start it but wouldnt fire.

Replaced the Crankshaft Sensor and it worked fine, got it to the auto electrician to clear the code and ran well for a little.

Back down the highway it started jerking and the revs would drop right off until the engine just stopped. Closer to home it started getting a lot worse to the point that it would never run perfectly for any length of time.

If i stopped at a set of lights i would have to put it into neutral just so i could keep the revs up to stop it dying. Then at points while driving the revs would drop off and come back at random, giving it more revs to get it back up would cause it to jerk and stutter uncontrollable and backfire occasionally.

Have read so far about some issues with the ECU and the Cat but are still waiting to test those at the moment.

Does anyone else have any ideas as to what could be doing this? Any other ideas would be very helpful so I can add them to the list to get done while I'm at it.

Will be looking to replace the spark plugs, leads, distributor cap, fuel and air filter soon.

The car is currently sitting in the driveway and will turn over but wont start properly. I managed to get it to fire once with a bit of throttle but it died off almost straight away.

Thank you very much for any help, hopefully I can get this jeep back to its original glory after it was ruined by whoever had her before me.

xpsniper~

*edit;The fuel supply has been checked, the pressure is good and it's getting a good spark, but both seem to go off randomly from what I've been seeing.
When i was first driving it on the highway the revs would drop down and sit constant at 1200 when i never moved my foot from steady 2000. When it would drop down I would coast and the rev meter would respond again so I'd give it abit a juice and it would go up, then drop down to that 1200 set point. Rinse Repeated the whole way home thinking that maybe the fuel just needed a chance to flow back into the engine (clogged filter or something :/) but that was all before the misfiring and dying that its currently doing.

No check engine light either.

RTorrez1

Where did you get the CPS from? After market one are crap! Most of the time they are bad right out of the box and if they do work they have a very short life to them. I would suggest to check out the CPS along with clean all of the grounding points. One bad ground can cause a lot of strange problems with our XJ's Here's a link to Cruiser's check list. Check out his #1 and #7 post.

xpsniper

The CPS is after market from a part supply chain in Australia, Repco. It was the brand recommended by 2 auto electricians.
The jeep isn't giving out any codes with the new sensor, no check engine light.

I'll check all the grounds and give them a clean and I'll check out the link when I get back home.

Thanks for the advice