4.0 runs good @ idle, stalls when put in gear?

[Tommy]

A co-worker just hit me with this question. The engine will idle and rev fine in Park/Neutral. Once they drop it into gear, it will sputter and backfire. They have replaced the MAP & TPS sensors, convertor, fuel filter.

I thought it sounded like starvation once a load was put on the engine, but the backfire seems like possibly timing.

Any thoughts??

[Happy Bear]

I've had a motor backfire while starving for fuel, I'd try to hook a fuel pressure gauge up while it's stalling.

[67temp]

Is the CEL on?

I've had faulty o2 sensors and the fuse cause mine to sputter and back fire underload, but in park would be normal till it got warmed up. Once warmed and idling it would surge in rpms trying to adjust itself.

[Will_M]

Had the same issue. If that Jeep has a coil, try replacing that.

[Tommy]

Thanks. I'll pass this along. The CEL is not on.

[glenburnieredneck]

My dad had this happen in a dodge he had. The distributer cap was cracked, once he replaced it....ran great.