Hello, thanks to all that assisted in my previous issue. Ok so the new issue is once my 96 ZJ 4.0 is at full operating temp it develops hesitation under load and will buck and bog at WOT. I have new plugs, tps, fuel filter, both O2 sensors and cleaned throttle body. When the jeep is cold runs normal and strong, once its warmed up it will not go WOT only bucks and bogs down until i let off a little.
I am really not sure where to look now? Would the MAP sensor cause issues like this? Fuel pump seems ok and it starts fast.
I have not tried that yet, the sensors are bosch. So what should i look for when testing this? Thanks
Just unplug it and warm it up, then see if it bogs and acts stupid. If not...it was the Bosch sensor. If so, we look into other things.
My initial thought was TPS, but since it seems to work fine in open loop mode, I think we can eliminate that as a cause.
It wouldnt hurt to remove the coil and see if it's cracked on the back side, either. But usually a bad coil will eventually cause the PCM to kill the engine, not limit the revs....which brings us to Zeejays question...(assuming he thinks it's a timing related issue.)