Weird stutter around 35 mph

[dyllant]

So I recently got a 2000 TJ sport with the 4l engine and 3 speed auto trans. The jeep was in really bad condition when my dad bought it for $1000, couple months later and him and I have fixed it enough for me to take it with me when I went back to college. Still a couple of problems though with the big one (and topic of this post) being a weird stutter I get when going around 35 mph. It doesn't always happen, but usually occurs when going up hill and wont happen at all if I accelerate past 40. I replaced the O2 sensors thinking that could be part of the problem since they had never been replaced and the vehicle had 190k miles on it. That seemed to make the issue go away, but a day later it came back just not as bad. Anyone have any ideas or troubleshooting steps I can take to diagnose this issue?

 

[macleanflood]

Any codes?

Try Seafoam? Couple posts about how to do that.

-Mac

 

[Gollywomper]

What brand O2 sensors did you use?

 

[dyllant]

Was getting O2 sensor codes before I replaced them, haven't check since. And for O2 sensors I used the NGK O2 sensors listed for my jeep in the O2 sensor thread here.

 

[Gollywomper]

Speed based sounds like a possible transmission issue.

 

[CharlesHS]

What is the ATF level in the transmission?
What color is the transmission fluid; should be pink to light red ?
When was the last time the fluid and filter were replaced?
Couldn’t hurt to have the system flushed.

 

[NskLJ]

So I recently got a 2000 TJ sport with the 4l engine and 3 speed auto trans. The jeep was in really bad condition when my dad bought it for $1000, couple months later and him and I have fixed it enough for me to take it with me when I went back to college. Still a couple of problems though with the big one (and topic of this post) being a weird stutter I get when going around 35 mph. It doesn't always happen, but usually occurs when going up hill and wont happen at all if I accelerate past 40. I replaced the O2 sensors thinking that could be part of the problem since they had never been replaced and the vehicle had 190k miles on it. That seemed to make the issue go away, but a day later it came back just not as bad. Anyone have any ideas or troubleshooting steps I can take to diagnose this issue?

I would look at the ignition system.

 

[KodiakTJ]

Had same problem in my 99. Replaced tps with mopar. Problem solved.