ok my buddy has a 97 cherokee 4.0 auto 4x4 his upstreem o2 sensor is bad he said his jeep died lastnight? it wont start now just cranks? he has replaced
Pickup coil
distributor cap and rotor
cps
and a few other things i stumped only thing i can think of is it was running lean and motor is junk but sounds like it got good compression ? some one please help

 

Check the fuses.. Check the wiring harness to the O2 upstream.. Sometimes the wiring get misplaced and melts on the #1 exhaust port and grounds itself.

 

A bad O2 sensor will not cause a no-start. I suppose a wiring fault, as Dan mentioned, could pull the PCM voltage low enough to cause problems...not really sure.

 

Do you know for sure it's ignition-related? Is the fuel pressure good?

 

I've had this issue before with a dies while driving.. No start after.. Found wires grounded and blown fuse.