Touchy Throttle Response

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Rick2004LJ

TJ Enthusiast
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Jun 11, 2018
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159
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Texas
2004 LJ Automatic used only as a Trail Rig - we are new to TJ/LJ's having been wheeling a '14 Unlimited manual.
The throttle is touchy/jerky when you first start to move, especially on the trail as you try to climb a rock or ledge. It feels like as you press the accelerator there is a lag then it lurches forward - and when it lurches you immediately let up (either because it lurches so hard it pulls your foot off the pedal a little, or just human nature as you accelerate way faster than you intended) and then you get back on the pedal and it lurches again. Rinse repeat until you get momentum and can maintain a steady throttle. It is probably not as bad as I am describing, but it is totally impossible to slowly creep onto an obstacle from a stop or slow roll.

Anyone else ever have this problem?

It feels like the throttle linkage is sloppy but me and mechanic have been all over it and there is no evidence of play or slack? Any chance it could have to do with the throttle body or some other part of the fuel system? There are no problems with a rough or low idle, no missing etc.

Any info based on similar experiences would be appreciated!
 
Can someone share the part number for that spring? I have felt the same "lurching" and if adding the spring makes that better, I will go ahead and add that for my '05.
 
Last edited:
JeepZilla380 said:
https://wranglertjforum.com/threads/missing-throttle-return-spring.12513/

I think I’m 03/04 they removed the extra throttle spring. We talked about it in that forum post. Mine was just as you described, added the spring and much easier to control now.
Click to expand...

I dont have a spring or anywhere to attach one. My setup is like the pictures posted by KCsTJ on the thread mentioned above.

But that brings up a question. There are 2 cable controlled connections - 1 goes to the accelerator pedal, what does the second cable controlled connection do? It looks like maybe it goes to a vacuum unit?
 
Rick2004LJ said:
I dont have a spring or anywhere to attach one. My setup is like the pictures posted by KCsTJ on the thread mentioned above.

But that brings up a question. There are 2 cable controlled connections - 1 goes to the accelerator pedal, what does the second cable controlled connection do? It looks like maybe it goes to a vacuum unit?
Click to expand...
On my 2.5L automatic that 2nd connection is a cable that goes to the automatic tranny.
I could be wrong but I think it is a kick down cable, so when you stomp on the gas pedal it downshifts to the lower gear.
 
Rick2004LJ said:
2004 LJ Automatic used only as a Trail Rig - we are new to TJ/LJ's having been wheeling a '14 Unlimited manual.
The throttle is touchy/jerky when you first start to move, especially on the trail as you try to climb a rock or ledge. It feels like as you press the accelerator there is a lag then it lurches forward - and when it lurches you immediately let up (either because it lurches so hard it pulls your foot off the pedal a little, or just human nature as you accelerate way faster than you intended) and then you get back on the pedal and it lurches again. Rinse repeat until you get momentum and can maintain a steady throttle. It is probably not as bad as I am describing, but it is totally impossible to slowly creep onto an obstacle from a stop or slow roll.

Anyone else ever have this problem?

It feels like the throttle linkage is sloppy but me and mechanic have been all over it and there is no evidence of play or slack? Any chance it could have to do with the throttle body or some other part of the fuel system? There are no problems with a rough or low idle, no missing etc.

Any info based on similar experiences would be appreciated!
Click to expand...
my 04 Rubi auto does the same thing ....added a spring didn't help ...changed TPS did not help ....still searching for an answer
 
I’ve noticed the same thing with my 6 speed. Very annoying going over rough terrain or going slow on washboard roads. Is very choppy. If you find a fix keep us informed.
 
1945GPW said:
I’ve noticed the same thing with my 6 speed. Very annoying going over rough terrain or going slow on washboard roads. Is very choppy. If you find a fix keep us informed.
Click to expand...

Thats how mine was, a pain over rough terrain, here is what I did to fix it. Spring kit from Autozone.
d42b6ef0d1fad7638b047c641d3174bf-jpg.jpg
 
My 00 4.0 5 speed did the same thing until it warmed up. I also had problems with the idle not dropping at stop lights with the a/c on. I cleaned the throttle body and stepper motor without removing the throttle body, (did remove the stepper motor) using CRC throttle body cleaner. Helped for a while then both symptoms returned, though not at the same time. This time I removed the throttle body, found out there was a lot of area that cannot be reached from the top, cleaned it this time with break clean, and replaced the stepper motor with new. Neither problem has returned much nicer to drive cold now.

B
 
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I put a heavier spring on mine too. There was a pack available at Oriellys with a bunch of different sizes. Ive been running that same spring now for 4 years.
 
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Back when jeep engines still had carburetors an additional throttle spring was a common "fix" for a jerky or oversensitive throttle in low range on rough terrain. The idea was to make the throttle stiffer to reduce pedal movement from minor foot pressure changes.. Another method was to lightly brace the right edge of the throttle foot against the transmission hump to reduce foot movement during bumps..

I used an additional throttle spring for the Hesco fuel injected 258 engine in my CJ-7. I haven't felt the need in my LJ, but I still have a collection of old throttle springs in my bins of miscellaneous fasteners and hardware "just in case."
 
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When I put a mc2100 carb on my 258 I fabbed up a bracket with two big ole springs to help with the touchy throttle response. Getting rid of the emissions crippled Carter carb was one of the best thing I ever did for that engine.
 
I’ll give the extra spring a try and see how it works. Has that extra resistance given anyone any problems with the cruse control?
 
1945GPW said:
I’ll give the extra spring a try and see how it works. Has that extra resistance given anyone any problems with the cruse control?
Click to expand...

I didn't have cruise control on my jeep with the extra throttle spring. Try it and let us know whether it causes issues with your cruise control. If the two are incompatible you won't be out much - throttle springs are cheap and removal takes just a few seconds..
 
Rick2004LJ said:
I dont have a spring or anywhere to attach one. My setup is like the pictures posted by KCsTJ on the thread mentioned above.

But that brings up a question. There are 2 cable controlled connections - 1 goes to the accelerator pedal, what does the second cable controlled connection do? It looks like maybe it goes to a vacuum unit?
Click to expand...
This is right up my alley. Being that I have a few YJ Wranglers from the 90’s I am very familiar with this issue on the 4.0.

The fix is an old school Jeep modification. Seen tons of YJ’s with them back in the day. My brother’s Jeep has one and I just used it on our trip to Coopinger Cove Tenn, check my threads to see pics from the trip.

https://www.quadratec.com/products/...MI16e4t-rt3QIVQlcMCh3fJQcEEAQYASABEgJNZfD_BwE
B3AEB253-86C2-404E-A8D8-B8604055482F.jpeg
 
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