When cold, engine is slow to reduce rev's when gas peddle released???

[crusty]

Hi. I just purchased a 2004 sport and when the engine is cold when I press on the gas and release (very noticable when shifting) the rev's are slow to reduce. I though it was a sticky throttle mechanism on the engine and sprayed it with WD-40 but that has not helped. My next thought is that the cable between the gas peddle and engine throttle is dirty and sticky, so I might clean or lubricate that.

Has anyone else experiance this and if so offer any advice?

Thanks in advance for your input.

Rick

[Rubi03 jef]

you can do some fast tests to find out if its the cable

one  -   open hood engine running twist the throttle body with your hand and release it see if it does the same as if u were touching the gas pedal

two -  engine running use ur hand push down on gas pedal and then pull up fast see if it still does it

if it does  continues to do it with option 1 then its somethign to do with the throttle body

if it does it in option two then its in the cable

[binare]

Was it warm? Sounds like the automatic choke.

[crusty]

That's a joke: right? 

[RckyMtnTJ]

There should be a spring pulling the throttle cable back, should there not?   Pretty sure there is supposed to be,  mine does not have the spring.  Mine is more noticeably slower to return to idle as well.

[binare]

That's a joke: right? 

No, justca poor choice of words... im old school. Check your butterfy plate in the airbox... make sure its opening and closing properly.

[BUKI]

Isnt this the main issue when the idle air control motor starts going.  Not the tps but the other sensor thing on the tb

[RckyMtnTJ]

Here is what I am talking about:

With Spring:


Without spring:


Here's a writeup on adding a spring.  Apparently some of the newer TJ's never came with one.

http://tmar.net/throttle_spring.htm

[crusty]

Wow RckyMtn! That sounds like my problem. No return spring. I'll try that and let you know.

Thanks to everyone for their advice.

Crusty

[Slewfoot]

Here is what I am talking about:

With Spring:


Without spring:


Here's a writeup on adding a spring.  Apparently some of the newer TJ's never came with one.

http://tmar.net/throttle_spring.htm

I have an '06 which doesn't have the spring.  I wonder if Chrysler left it out because they changed something in the cruise control and needed less resistance on the throttle...any thoughts?

[hps4evr]

I have an '06 which doesn't have the spring.  I wonder if Chrysler left it out because they changed something in the cruise control and needed less resistance on the throttle...any thoughts?

someone may have to correct me but i dont think there ever was a return spring like that on the throttle. there is one on the outside of the throttle body on the butterfly, should return the buttefly fine. that spot is for the automatics with a throttle valve cable. fuel injected version of the old kick down cable.

[FiEND]

i think you are right.  I have noticed sometimes before that we have no spring, only when I am looking around that area.  I will check mine when I go down.  in the pictures it looks like the spring is built in under the throttle cable itself.. but then I don't know what the brown ended cable is for (speed control cable)  and yes, the pictures show the automatic having a kickdown cable attached where they put the return spring above.

[frenchy]

Wow RckyMtn! That sounds like my problem. No return spring. I'll try that and let you know.

Thanks to everyone for their advice.

Crusty

I have that extra spring. If I disconnect it, everything still works fine.

Is your gas pedal physically not returning to the top? I'm sure you would've mentioned that but just checking.

Are you sure your "rev's slow to reduce" problem is not just the sound of your fan clutch not disengaging? Rev it manually from under the hood to check.
If that's fine, and your pedal is coming up fine, sounds more like a sensor issue. Remove throttle body and spray it all out with brake cleaner. Scrub with emery cloth. Spray. Scrub. Spray. Wipe down, install and re test.

[Slewfoot]

someone may have to correct me but i dont think there ever was a return spring like that on the throttle. there is one on the outside of the throttle body on the butterfly, should return the buttefly fine. that spot is for the automatics with a throttle valve cable. fuel injected version of the old kick down cable.

That would explain why I've seen the spring on some engines. (I've been curious about that)  I have a 6 speed manual.

i think you are right.  I have noticed sometimes before that we have no spring, only when I am looking around that area.  I will check mine when I go down.  in the pictures it looks like the spring is built in under the throttle cable itself.. but then I don't know what the brown ended cable is for (speed control cable)  and yes, the pictures show the automatic having a kickdown cable attached where they put the return spring above.

One cable is for the accelerator pedal, the other (there bare one with the brownish end) is for the cruise control.

BTW, my revs drop fairly quickly - cold or hot.

[crusty]

OK, This is what I found out. When cold, manually operating the throttle under the hood does not change the slow rpm quickly so I feel that the return spring won't solve my problem. However I may still install a throttle return spring for less than $10 at the dealer. This will help with the "This makes the throttle very sensitive and hard to control over bumps at low speeds" quoted in the link from RckyMnt.
I checked my TJ service manual and it appears the nub on the throttle leaver for the return spring is there for the connection for the optional cruise control.
So I guess my next step is to clean the butterfly valve when the weather warms up.
Again, thanks to all for advice. I will repost when I clean the butterfly valve.
Crusty