Throttle Body Sticking
Thread Starter
Instructor
Joined: Jul 2008
Posts: 101
Likes: 0
From: Bartett/Long Grove IL
Throttle Body Sticking
I was having sporadic idling 
so, I cleaned out my throttle body, and now when i throw the car in neutral the RPMs remain as if they are in gear. (If I was driving at 2,300 RPMs then it will idle at 2,300 RPMs for 2 minutes) I figured it was sticking so I sprayed WD-40 on the exterior left controller, but the problem still remains. My only other thought is spraying WD-40 on the inside of the throttle body.
Does anyone else have any thoughts?
so, I cleaned out my throttle body, and now when i throw the car in neutral the RPMs remain as if they are in gear. (If I was driving at 2,300 RPMs then it will idle at 2,300 RPMs for 2 minutes) I figured it was sticking so I sprayed WD-40 on the exterior left controller, but the problem still remains. My only other thought is spraying WD-40 on the inside of the throttle body.Does anyone else have any thoughts?
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 411
From: WV
It sounds like either the ( IAC ) is gummed up,a sticking cable like mentioned above, or the shaft in the throttle body is binding. The shaft eats out the holes that it rides in and causes the shaft to bind. I have seen this on 2 throttle bodys, I believe you can have it drilled and have bushings put on the shaft but I forget who does this. Maybe another forum member can chime in and tell you where to have this done if this would be the problem...WW
Burning Brakes
Joined: Apr 2006
Posts: 765
Likes: 0
From: Houston Texas
I just changed my IAC valve and after cleaning the T/B, I put a drop of sewing machine oil on the butterfly shaft at each bearing point, now it sticks just open. I can push the T/B closed with my finger at the screw stop. There's no slack in the bearing points.
I adjusted the IAC after installing it. Its not the IAC valve causing it. I think I just need to drive it a little more. Is there an easy way to lubricate the cable in it's housing?
I adjusted the IAC after installing it. Its not the IAC valve causing it. I think I just need to drive it a little more. Is there an easy way to lubricate the cable in it's housing?
Thread Starter
Instructor
Joined: Jul 2008
Posts: 101
Likes: 0
From: Bartett/Long Grove IL
I also replaced my IAC. I don't know what could be causing this, recently its been sticking less since it seems to be getting colder out. Once my car warms up it sticks more often, I am also getting a "Check Engine Light" on hard acceleration. When I plug the code checker in all I get is code 12. Which is a nothing code.
I am very much new to cars at this point, but could it have anything to do with coolant not running through my throttle body properly? The reason why it only works properly when the throttle is naturally cold. I also noticed there was some old coolant residue on the bottom inside triangle in the bottom center of the throttle body when I took the gasket off.
I am very much new to cars at this point, but could it have anything to do with coolant not running through my throttle body properly? The reason why it only works properly when the throttle is naturally cold. I also noticed there was some old coolant residue on the bottom inside triangle in the bottom center of the throttle body when I took the gasket off.
Burning Brakes
Joined: Apr 2006
Posts: 765
Likes: 0
From: Houston Texas
I just changed my IAC valve and after cleaning the T/B, I put a drop of sewing machine oil on the butterfly shaft at each bearing point, now it sticks just open. I can push the T/B closed with my finger at the screw stop. There's no slack in the bearing points.
I adjusted the IAC after installing it. Its not the IAC valve causing it. I think I just need to drive it a little more. Is there an easy way to lubricate the cable in it's housing?
I adjusted the IAC after installing it. Its not the IAC valve causing it. I think I just need to drive it a little more. Is there an easy way to lubricate the cable in it's housing?
I hope I don't have to take it back off and see if it is binding somewhere. I did tighten the ever-so-famous hi-power air foil...hope I didn't warp the TB enough to make it bind.
Never did this before the cleaning and reinstalling with the new IAC valve and gaskets. And was very careful with the cable while removing and replacing it on the TB.
Oh these LT1's...where are the simple carburetors and distributors?
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
are you sure its not the accelerator pedal getting stuck ?
try pull it back with your toe when it gets stuck,then tell us what happens
What happened to me is that a plastic/foam panel under the dash was
interfering the pedal mechanism travel there,in a intermitent way,so it didn't happen all the time and was driving me crazy,everytime i thought it went away ..it came back!
So i removed it and reinstalled it in the proper way.- problem solved !
And clean that TB like hell ! make sure the spring is working
try pull it back with your toe when it gets stuck,then tell us what happens
What happened to me is that a plastic/foam panel under the dash was
interfering the pedal mechanism travel there,in a intermitent way,so it didn't happen all the time and was driving me crazy,everytime i thought it went away ..it came back!
So i removed it and reinstalled it in the proper way.- problem solved !
And clean that TB like hell ! make sure the spring is working
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Instructor
Joined: Feb 2008
Posts: 143
Likes: 0
From: Chesapeake VA
Wow, this seems to happen to all of us. I just noticed that mine is doing the exact same thing. But as Calderone said, its probably the foam up by the pedal so that is what I'm going to check when I get home tonight.
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
I Really really thought it was a lubrication issue,then i checked the spring as it didn't pull the throttle to the back,so i guessed it was the spring,but i took off the underdash plastic panel to find out that there were some foam and some box with cables that got loose ,so the foam,plastic and this box was obstructing the pedal to travel back,and i was about to buy a brand new cable.-
Check that ! unbolt and bolt everything that might be obstructing the travel there...
and try to correctly position the panel,it was no easy for me,because it didn't fit in some angles,and i broke it in some points,but nothing noticeable,and i had to use a bigger shim on the support bolt (that prevents the rear area of the panel to fall down) on the firewall.-
Now my gas pedal travels better than ever !
Check that ! unbolt and bolt everything that might be obstructing the travel there...
and try to correctly position the panel,it was no easy for me,because it didn't fit in some angles,and i broke it in some points,but nothing noticeable,and i had to use a bigger shim on the support bolt (that prevents the rear area of the panel to fall down) on the firewall.-
Now my gas pedal travels better than ever !
Instructor
Joined: Jun 2024
Posts: 104
Likes: 15
From: Sacramento, CA
I know this is an ooold thread but my 89 6 speed L98 has this issue only when the car is at operating temp and running. Anyone ever have an answer for this? Throttle body is new, had same issue with original throttle body. It will stick around 2000-2500 rpm but only when the car is running. You shut it off and it's fine. Cruise control cable has already been d/c. Throttle cable has slack.
