Touchy throttle response. Unable to maintain less than 1300 rpm.

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Fugitive

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Nov 22, 2022
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6
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Houston
4.0L idles at 750. If I crack the throttle the tiniest bit the engine speed increases to 1300. Close the throttle, back to 750. It is not possible to maintain rpm (with no load) between 750 and 1300. It's most noticeable while driving in traffic in low gears like 1st or 2nd. The slightest crack of the throttle commands significant torque. There is no way to accelerate smoothly without using the clutch.

My TPS reads 15.7% at closed throttle and increase smoothly with no dead spots. I've noticed that the ecu has the timing usually at 10 degrees at idle and and idle plus 0.00001 throttle it jumps to 25ish degrees. Any thoughts?

Thanks.

2000 Wrangler, 5 speed manual, 4.0L, stock.
 
I’ve got a similar thing going on. Coming down a hill that you need a bit of throttle to maintain speed my Jeep will jerk forward with just a bit of throttle or back off when you let off the throttle. I figured it’s just the way it runs. I’ll have to try it when it’s sitting still and see what happens
 
Thanks to @CharlesHS for the video showing how to test the tps. Finally got out here to test mine, thought it might be part of my jerky running. I used a Simpson 260 meter instead of the dvm. My tps is smooth as silk all the way across from idle to wide open throttle.
Still ordered a genuine mopar tps from rock auto. $15 at the local parts store. The genuine mopar was $87 shipped and taxes.
Got a spare now if mine ever dies. Probably won’t since I’ve got a spare🤞
 
So does everyone’s 4.0L TJ respond like this…idle at 750 and jumps to 1300 as throttle is cracked? I’m unable to maintain anything between 750 and 1300.
 
I have a very similar issue with my '97 with the 2.5L. Idle around 750-800 and if I so much as breathe on the throttle I jump to 1100 or so rpm.
 
Hi all. Long time lurker, first time poster. Any updates or fresh ideas on this issue? My LJ does the exact same thing, jumps to 1300 rpm at the slightest touch of the throttle.
In the past month;
-Cleaned throttle body
-New air filter
-New Mopar IAC
-New Mopar TPS
-New Mopar MAP Sensor
-New catalytic converters
The problem persists and I haven't been able to track it down. I've haven't been able to find any vacuum leaks. Any ideas? Thanks in advance.
 
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