Maybe some of you guys can give me some insight on a weird quirk I've had way too much experience with on these last generation XJs with the 4.0. Being new here, I apologize if this was expounded on previously, but it is puzzling me to a major degree.

On the previous '97 Sport we no longer have (too much rust and other issues), the current one and the '98, I've replaced the throttle position sensors, some multiple times. On the '97 Sport we sold a few months ago which I had for the past 11 years and ran for over 225,000, I replaced no less than three TPS. On the current '97 the wife now drives, I recently replaced the motor in March at 235,000 and installed new sensors on the 80,000 mile replacement. The original engine went through two that I know about. I bought it 6 years ago with 150,000 and put a lot of highway miles on it. I replaced the TPS again this morning. The '98 Classic got a new one yesterday at 173,000 which cured a no start when cold on the first try issue. I don't know if it was replaced prior or not as it was a recent acquisition. I just can't tell. The '97 just plain wouldn't start this time even though it wanted to which was unusual as the previous failures showed as performance and starting problems, but the cars never completely broke down as was the case this morning. It was running poorly on the wife for several days before which after she told me, I believed that this problem was rearing it's ugly head again. It runs perfectly now after I blew the crap out if it that accumulated from the no start condition.

Oh yeah...no DTCs in every incident other than the misfire codes that were created by the sensor failure.

So, why do these sensors seem to have such a high rate of failure? I haven't replaced hardly any other sensors on all three vehicles in the past 11 years. If it was all on the same XJ, I might be suspicious of the individual vehicle. That isn't the case. Also, the sensors weren't bought at the same parts outlet. They have been mixed between Advance, Auto Zone, and an independent.

Ideas?

 

no idea..my buddy has a TJ 4.0L and everytime he goes mudding his TPS craps out, he's on his 3rd one.

i've had my XJ for about 4 months, im on my 3rd as well.
i do suck in a little water thru the intake here & there..maybe thats my problem.

 

My '96 still has the original! I bought another when troublshooting a trans issue, but put the original back in because it was sealed and the replacement was not. Buy your next from your Jeep dealer?