98 XJ Sport bogging, stalling, hesitating.

[NHxj4x4]

Hey guys, been a while.

Posting for my mother-in-law and her 98 Cherokee 4.0L Auto.

So far I have replaced the TPS, MAP, plugs, wires, cap, rotor with spares that I had laying around.

The Jeep is running very poorly when cold. It starts rough, stalls, bogs, hesitates etc until it's up to full operating temp. It's dangerous in traffic and we're not comfortable letting her drive it right now. Even at temp, it still does it, but it's much less frequent. When it's not doing this the Jeep runs extremely well.

Any thoughts on what would be causing this past what I have replaced would be appreciated.

Thanks,

Todd

 

[joe_peters]

Test the Coolant Temperature Sensor--in the thermostat housing. I don't have specs for the 98, someone else will pipe in I'm sure.

 

[NHxj4x4]

Test the Coolant Temperature Sensor--in the thermostat housing. I don't have specs for the 98, someone else will pipe in I'm sure.

I can certainly try to swap my spare out, anyone think the IAC could cause any of this shit?

 

[89xj]

is the CEL on? any codes?

no, i doubt the IAC has anything to do with it. is the throttle body dirty?

have you tested fuel pressure when its running bad?

what have you tested?

sounds like your just swapping parts in without testing.

 

[NHxj4x4]

is the CEL on? any codes?

no, i doubt the IAC has anything to do with it. is the throttle body dirty?

have you tested fuel pressure when its running bad?

what have you tested?

sounds like your just swapping parts in without testing.

TB is OK, I want to do a seafoam treatment but haven't had time. CEL is not on and nothing hidden seen by my scanner. Have not looked at fuel PSI. I don't believe it to be fuel related as the problem somewhat goes away when the truck is warmed up.

I am indeed just swapping stuff in right now, but at least they are educated guesses. I had a similar issue in a 93 ZJ and the TPS cured that.

 

[89xj]

well if your replacing sensors, then that leaves you with the CTS(as joe stated), o2 sensors, and cps.

i would go with joe because it is temp related, but with a cold engine. if it were with a hot engine, i would say cps or coil.

 

[NHxj4x4]

well if your replacing sensors, then that leaves you with the CTS(as joe stated), o2 sensors, and cps.

i would go with joe because it is temp related, but with a cold engine. if it were with a hot engine, i would say cps or coil.

I'm doubting CPS as it's never a "No Start" issue, just rough starts. I'll change the temp sensor out and see what we get.

 

[Shorty]

could still be a fuel delivery problem-- engine needs more fuel cold (richer mixture) than hot-- if it were on the "ragged edge" of insufficient fuel pressure hot, it would give you headaches cold.

 

[joe_peters]

could still be a fuel delivery problem-- engine needs more fuel cold (richer mixture) than hot-- if it were on the "ragged edge" of insufficient fuel pressure hot, it would give you headaches cold.

Good call, Shorty--could explain why the problem remains but is largely reduced when warmed up.

 

[4wheel98cherokee]

Don't forget to check your grounds! My 98 had very similar issues, cutting out, stalling, no start, I cleaned all the engine grounds under the hood that I could see and she runs great now.