Hey all,

Been dealing with this issue for quite some time. Been searching and throwing parts at this thing trying to resolve the issue. It will start right up, but after running for some time it will begin giving me issues.

Vehicle: '98 XJ, 4.0, AW4.

Problem: Typically when ambient temps are above 50* and the Jeep has been running for some time in any gear it will begin to sputter and misfire. If I let it just sputter it will eventually stall out and shut off. If i hold down the gas pedal, it will sputter and backfire and may recover. However, it will create the same condition again.

What I've replaced:
Plugs, Wires, Cap, Rotor, Pickup Coil, Ignition Coil, Crank Position Sensor, Fuel Pump, IAC, TPS, Ignition switch, Checked grounds, Battery, Alternator, Starter, Junkyard fuel rail & injectors from ZJ 4.0.
(All parts are under 1.5yrs old)

Fuel pressure reads 30psi when key turned to run and 40psi at idle. Issue?

Any thoughts or help?

 

Tried replacing coolant temp, iat, and map sensors today. Also, unplugged both o2 sensors. None of these things made a change.

Video of what its doing. Hood open, engine idling, engine temp around 200*. Outside temp between 55*-60*.
https://youtu.be/awRggTK9z0U

 

Is it stuttering or shuddering?

 

Do the RPMs stay constant? It sounds like it's revving up when you walk back to the front right before it stalls.
Also, this only happens when it's warm out?
Are the throttle body and IAC clean?
You replaced the TPS, but could it be bad?
I don't know what's going on, just trying to think what I'd do if it happened to me.