I just got my XJ, it had trouble starting, replaced battery and now it starts fine, but while on the road cuts out when the motor is turning 1000-1500 RPMs. Does only acting up with this RPM range single out any one problem? I have heard clean throttle body which I plan to do this week, also fuel pump or crank sensor... Just wondering if I can narrow down my options to fix as I don't have a bunch of money to throw at her currently. thanks in advance.

 

Clean your idle air control thing too. its screwed into your TB with 2 small torx bolts.

 

It MIGHT be the throttle position sensor going bad. Its on the throttle body.

 

thanks, I just picked up a TPS, plan on replacing that and cleaning the TB tonight. I'll let y'all know if that was the issue...

 

What you describe is a "classic" symptom of a bad throttle position sensor as excess650 mentioned.

They can have a bad "spot" on the sweep which gives you symptoms only at a particular rpm.

Definitely get that TPS in there and let us know if it resolves it!

 

ok, cleaned the Throttle Body real good, and replaced the TPS... and the issue is still there, maybe 20% better. Seems to have a slight shifting issue too. I have a CPS that I was about to return bc it was $80, but could that be an issue combined with TPS? Also I have no cats and no pipe after the Dynamax (bought this way) Could this be affecting anything? Has a little back fire when it shifts sometimes.... thanks again guys.

 

1996 should have an O2 sensor after the CAT, so if you're missing the the sensor and cat, the computer may not be happy.

 

I thought only 97+ have those?

 

Rednek -- Do you have this problem at all temperatures? It sounds pretty similar to a problem I'm having (just posted a thread about it, actually), but I only get it when it's warm outside (over 60, maybe). I replaced the TPS last year because I was getting a "bad voltage" code for it. Would be really annoying if that new TPS was going bad already.

 

I have a '90 that is doing some of that too, replaced the TPS supplied by the guy who had the jeep prior to me buying it. The sensor was brand new since it was still in the box. The problem kept happening, so I've been steadily replacing dry-rotted and oil soaked nasty vacuum lines and fittings, the problem seems to have either gone or has been drastically reduced so far.

 

My '96 has most definitely an O2 sensor after the cat. I bought the Jeep new in June of '96 and it was my wife's DD for 10+ years.

 

fairlycrass, I live in Orlando, its currently 105 in the shade. So I only have hot to go off of. TPS, CPS, TB cleaning, and nothing... I drove about 70 miles today and the problem actually seems to be worse! I guess I will go try and pull a cat and sensor from a yard. I rode for a while in in 3rd gear that seemed to help keep the RPMs over 2k and not cut out as much. It's killing me bc the motor runs great when doing 50-60 mph, So I know it's potential. I am taking to a guy that works on Jeeps that is willing to try and diagnose it for free just b/c I am going crazy here! If anyone else comes across another possible fix, please share. This is harming my feeling towards my first Jeep, haha.

 

I had similar problems as you are speaking of...would run great in higher rpms but sucked in lower rpms...for me it was the fuel control valve...got a new one and she ran like a champ.

 

When you say "fuel control valve," do you mean fuel pressure regulator? That is the other part (besides TPS) that I've replaced in the past year (TPS because I was getting a code for it, and FPR because there was a fuel leak, and I didn't want to monkey with finding the right size and type of o-ring).

Rednek -- I'm at the opposite end of the spectrum, in Laramie, where 85 degrees is a real rarity, even in the middle of summer. I only have to get to about 1200 or 1300 rpm before the problem seems to goes away, but maybe it's temperature. I saw a thread about a similar low-RPM problem, the fix for which was wrapping the #3 injector with heat reflecting tape, because it's too close to the manifold, and this somehow messes up the injection or burn rate or something. So, if I don't hear anything else, I may give that a try since it's about the cheapest possibility. Let me know if you resolve your issue.

 

Yeah thats what i meant...and mine did the same thing, and i got the o ring...and then it did what the op was saying, so i changed it and it fixed it.