Ok so me and my wife just bought a 4 1/2 in lifted 98 cherokee classic on 33s. Was told it had a problem and was promised it was the ECM. So i went to the local pic a part and got a used one thru it in and still having this issue as followed.... Drives fine sometimes but after awhile of driving it was start to spit and sputter, backfire and RPMs will jump up and down rapidly. Once u stomp on it and hold it floored it will clear it up. Also noticed when it starts to act up u can smell coolant in the cab. While sitting in gear with foot on the brake as the idle jumps the jeep will jolt forward.
OBD scanner read out 700 and 740 codes but also said i have high volts in 02 sensor 1 bank 1. 14 volts. Tomorrow i will be taking it to a uncle who is a mechanic and having codes cleared to see how long it will take to trip them again...
Anyone have the fix to this issue?