Hey everyone! I am new and this is my first post. My jeep is stock and I recently replaced the crankshaft sensor and coil after I had a no spark condition. After putting up with the following condition for about a year, now I want to fix it. I start it in the morning and it runs fine. After it reaches operating temp I park it. After 20 or more minutes parked, the restart is fine but it boggs down and even backfires up to 25 or 30 mph. I have to back off the gas for the engine to run . Once I rev it up or accellerate hard, It clears itself and runs fine , even at the low speed accelleration. I live at sea level. The engine seems to run better at higher elevation. Could that mean MAS sensor? Any ideas would be great.

 

It could be an O2 sensor. I had the same problem when mine took a poo on me.

 

Also I would clean the intake and throttle body. Also could be the IAC or TPS. Have you checked the plugs?? Pull the number 1 plug and check it for gap and fowling. If they look burned or nasty replace them. Also I would suggest new wires as well. To me sputtering or hesitation could be a vacuum/air issue, fuel issue or spark issue ie plugs,wires, cap, rotor and coil.

 

Thanks for the reply. Six months ago when I had a no spark condition my first action was to replace the plugs, cap, wires and coil. Then I replaced the crank sensor and that fixed the problem. The problem I am having now was the same before I had the no spark problem.

 

What is the IAC and the TPC? Good thoughts. I think it will boil down to fuel/air issue. I hunt Blacktail and hogs in Northern California, both rifle and bow. What do you hunt in Oklahoma?