Wizard, sorry for the late respnse, but I was away on vacation.....YES! ....I only got sputtering and hesitation when I accelerated to pass or hard off the line. Idling was fine, cruising was fine, only when I stepped on the gas for passing or from a start (hard). I hope you have the problem solved by now......

 

Sorry I dont mean to thread jack but I read in my manual something about these engines not having crankshaft position sensors until 2000, is this false? My XJ never starts on the first try and sometimes takes alot longer than others to start. It acts like the ignition is retarded to far, then every now and again it acts like its advanced to far. Sound like the CPS?

 

I got a 98 with 169,000 on it and its doing the same thing . does it completely stall out ?

 

Okay.. Sorry for the delayed post. but i wanted to make sure I did fine the fix before I posted what it was.

Recap,
98 XJ would sputter and buck when you accel. after replacing almost every sensor on the vehicle (MAP, CPS, TPS, O2 Upstream, Oil Pressure), replacing the ignition coil (that was cracked), new Plugs, Wires, Rotor and Cap; I still had the same problem. (not a happy camper!!)

Things got worse over time, engine would sputter and die out at the stop light.
So, One night I open the hood and allowed allowed the engine to idle, with the parking brake on and the transmision in drive. (not safe i know!!) but this allowed the engine to sputter and barely stay running. I was using poking and tapping different sensors to see if something would change.
what i found was the wire harness on the right side of the engine (from the firewall to the coil). by moving this part of the harnes by hand, the engine would stop sputtering and run fine, move it another direction engine would act up.
so my thinking was BAD CONNECTION!!.
After a few hours of not finding the exact bad connection, i decided to take that portion of the wire harness appart and look for shorts.

So what fixed the the problem as taking off the wireway covering, inspecting each wire and repairing a splice that is at the upper portion of the harness.

my opnion was that over the years that part of the harness is so close to the engine that when it got hot, the wires tended to melt together, while they didnt short out, there is a few wires for the sensors that utililze 5v supply and feedback a signal to the PCM, and thus effecting the true signal. the main sensor in mind would be the distributor sensor and coil.

anyway, after seperating semi-melted wires, repairing splice, etc. I have not had any trouble for over three (3) weeks, i drive it every day.

if you have any futher questions, i wil do my best to answer, as i have learned a lot from this nightmare!

 

pics?

 

I should have taken pics of the wiring problems as i fixed them, but due to my fustration trying to find the problem, I was not sure i was on the right track at the time.
I can post a pic of the wire harness location if need be.

 

Hmm I dont think this is my problem, but Im glad you got yours taken care of. Props for ripping into a wiring harness!

 

Congrats on fining the issue.
My 99 is doing this but only notice it after it sits over night, so on cold start it sputters under acceleration for a few mins. I can throw it in netural, rev it up, then back to drive and gas it and it sometimes works. If I let the jeep sit to warm up it dont do it.

I swapped TB's with sensors with my other XJ, same effect. Swapped air intake temp sensor, same. Then swapped coolant temp sensor and same.
Kinda out of ideas other than CPS but kinda think its something else.

Its only when cold starts.