Started stalling, backfiring, idling rough...
I changed plugs, wires, cap, rotor - No change
New Battery - No change
New coil - No change
New Fuel Pump and Filter - No change
New Crank Position Sensor - No change
Added new throttle position sensor - still rough idle
I have an exhaust leak on exhaust manifold...couple bolts missing, could that create a vacuum leak?
I'm also wondering about EGR valve, but it's about 110 to replace. Ouch!
The exhaust leak is throwing off the o2 sensor causing you to run rich and throwing off the calibration. On the pre 91 yj there is a setup procedure that must be done for the tps, ais, and wot when replacing.
Bad Spark Plug! Not cracked, not broken. I changed plugs, wires, rotor, and cap when my engine started running rough. And it didn't help. My mechanic removed plugs and tested them and found one that just was a dud. Running like a champ now!