YJ 4 cylinder cutting out at high rpm

gcheris

New member
We have a 1995 YJ 4 cylinder. It cuts out at high (3800-4000) rpm. We've replace fuel filter, coil, rotor, wires, and plugs as well as the throttle position sensor. I've heard that it could be the crank sensor and fear we may be floating tired valve springs. Any ideas would be appreciated.
 

What we had finally learned? The flex plate was somehow the issue. It looked fine, no issues when magnafluxed etc. However, replaced it with a used one that 'looked' worse fixe the problem immediately. All we could surmise that it somehow was flexing to far at 3000 rpm and moving the timing windows out of sight of the timing sensor.
 
Last edited:
Wow! Would not have been on the top of my list of things to check! Was the jeep throwing any codes?
 
Last edited:
Wow! Would not have been on the top of my list of things to check! Was the jeep throwing any codes?

Oops, sorry, I meant to say flex plate.

No, no codes. Like I we replaced everything we could think of. Finally we took it to a Toyota guru at a small shop Applegate, Ca, Zack, who loves a challenge no matter what vehicle. He we thru and temporarily replaced everything we had replaced just to check - same results. So he started following the spark and found that if he moved the position sensor it would create the same issue. He said he could not prove it but we replaced the flex plate it would solve he problem and it did.
 
Back
Top