Low Speed Cutting Out

[Jeepster97TJ]

I have a 97 TJ that I recently bought back in November. Since I have owned it I have put new plugs, distributor, rotor, and wires. I have pulled the throttle body and completely and thoroughly cleaned the throttle body. I first cleaned the IAC and that seemed to be the one thing that helped. Then all of a sudden it started doing it again (stuttering on take off or low speeds) just recently. I replaced the IAC, nothing changed, actually think it made it worst. SO I put the old IAC back on and it happens less but still happens frequently. I keep getting a code for the CAT but I have no CAT. I have an aftermarket header into a straight pipe back to the muffler. I still have the upstream sensor and the down stream sensor in there. Does that affect the way the engine runs? Could it just be a TPS? It only has 79K on it. I wish I understood what the sensors do and how that affects other things. Should they just come out since I do not have a CAT? Need some wisdom and knowledge from you seasoned Jeepers.

 

[macleanflood]

The original IAC is a Mopar? What brand did you replace it with, the new one?

On my 97 I was having O2 and cat issues. I ended up replacing my cat with a Magnaflow.

The front O2 does all the work...ran fine without the rear but got a CEL....put the original rear back in and it's been perfect since.

Generally speaking a working O2 will range below.9v. Might want to check that.

-Mac

 

[Jeepster97TJ]

The original IAC is a Mopar? What brand did you replace it with, the new one?

On my 97 I was having O2 and cat issues. I ended up replacing my cat with a Magnaflow.

The front O2 does all the work...ran fine without the rear but got a CEL....put the original rear back in and it's been perfect since.

Generally speaking a working O2 will range below.9v. Might want to check that.

-Mac

I picked one up at the local autopart store. I just returned it. Will the O2 mess with the way the engine idles/runs? When I get up and running I have no trouble. It's usually taking off out of a parking lot or pulling out of my driveway heading out. It starts jerking the truck (5spd) so I quickly push the clutch in and rev it a little and gently let the clutch out again.

 

[Danarch]

So does it only do it when the engine is cold? Once it’s up to operating temperature it runs fine?

 

[Jeepster97TJ]

So does it only do it when the engine is cold? Once it’s up to operating temperature it runs fine?

Well now that you mention it, it typically happens from cold start. I took it out on a mountain trail two weeks ago and it seems to do fine the whole time. I don't remember it ever cutting out or giving me trouble. It did it twice today. Once after it had been parked for a hour and the other time after it had been parked about 15 mins. After I initially cleaned the throttle body it rans amazing for a couple days then it started back up again.