Jeep Engine stumbling and running like butt.

[KarlVP]

So MY 97 ZJ (318 V8) started doing the strangest thing.

When you are sitting in traffic doing the "stop and go" thing. When you stop, it will Idle up about 250 RPM for a second or two, then dip way down low, then stumble and is fine. Sometimes it even dies. Starts right back up and acts fine. It only does this when the wife is driving, I can't duplicate the problem. I even had her take me around the neighborhood so I could see what she was talking about. It runs and drives fine, just stop and go no acceleration is when it happens.

No codes at all, no CEL. I'm stumped. I got a thing of carb cleaner and sprayed it at all the vacuum connections while running with no change in idle at all.

Last tune up was Less than 6K miles ago. I did plugs, wires, 02 sensors, cap & rotor, and seafoamed it.

Could this be a transmission or torque conver problem?

It does have the 27lb mustang injectors in it, high flow cats and underdrive pulleys. But they never caused a problem before.

:wtf:

 

[ToyZuki]

I have a 96 and about twice a year mine will do that until I pull the throttle body off the intake and hit it with chemtool. The blow by tube runs into the intake directly onto the throttle position sensor gumming it up. I should probably replace it but I always say carb cleaners cheaper-I'll replace it next time. I was supprised if you look closely your tb will say holley on it.

 

[Lincolnlock]

Or it could be the a/c compressor comming on and off and starting to lock up.

 

[KarlVP]

Or it could be the a/c compressor comming on and off and starting to lock up.

Ah, never thought of that. I'll try driving it around with the HVAC fuse pulled. Would that cure the problem?

 

[skrause]

Ah, never thought of that. I'll try driving it around with the HVAC fuse pulled. Would that cure the problem?

Just test by driving it the way you normally do and then turn on the a/c.

 

[tommyjohnston]

hey check your IAC or TPS. even the oxygen sensor will cause this. this happened to me and fixed it and it runs like new!

 

[ToyZuki]

hey check your IAC or TPS. even the oxygen sensor will cause this. this happened to me and fixed it and it runs like new!

Thats what it is on mine.

 

[pokey]

our 94 has a smalll pintle valve on the back of the throttle body that gets dirty and sticks causing exactly the same problem your describing. undo the 2 screws and pull it of and clean it with some carb cleaner or such. this is assuming their the same after 3 years. ours has the holley on it.

 

[KarlVP]

I cleaned up the IAC and throttle body with some carb cleaner last night. Drove it around some more, didn't notice it. We shall see what the wifey says when she gets home from sitting in traffic this evening.