Ok so my 99 Cherokee sport 4.0 has been giving me issues for a while. It wouldn’t start and than when it would it would run like **** and sounded like a misfire. I ran the code it there and it say cps so I replaced that with 3 different branded ones and the last one was mopar. Than it ran but when I would drive up hills or stop the rpms would drop and it would stall. It idled terribly and the rpm’s would be all over the place at idle. It sounded like a cammed car. Than I thought maybe idle air valve so I just replaced that. It still runs like **** and won’t really drive. When I give it gas it will bog and sputter and die and after I drove it around my neighborhood and let it get up to temps it would no longer start. It would try to start and than shutter very violenty and would die. I have no idea what it could be at all. I don’t really want to bring it to a shop bc it won’t make it there.

 

When's the last time the O2 sensor has been replaced?

 

Or a tune up and cleaning of grounds?
Fuel pressure?

 

I'm with Roler. Simple stuff first. Always.

**Are there any remaining codes now? Post the exact codes here for comment.

**Test your fuel pressure. Must be tested with a fuel pressure gauge, anything less is guesswork. The gauge can be rented from many parts stores inexpensively, call around for details. The fuel pressure spec for your 99 is 49.2 psi, plus or minus 5 psi.

**Tune-up. Fresh Champion copper plugs gapped to .035, quality plug wires, quality distributor cap and rotor.

**Freshening grounds is never a bad idea. Can't tell by looking at them. Disassemble, clean until shiny, reattach.

Good luck and be sure to keep us updated!

 

thanks for the help, I cleared the Codes and there was nothing else, i replaced the coolant temp sensor bc my friend said it could be that but that didn’t help. I will have to get the fuel pressure tester thing today to see if that is it. That’s what I suspect it could be but this whole thing started by it having a hard time starting after long drives and than eventually not starting at all and throwing a code for the CPS which I changed. I have been told to backprobe the sensors but I’m not sure of the process of that. Thanks for the help again

 

 

Check for exhaust occlusion.

 

And let's go back to your first post:

Does that mean it was running fine, and problems started after you changed it?