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Throttle sticking (not the cable)

This is a discussion on Throttle sticking (not the cable) within the Technical / Maintenance forums, part of the General Discussion category; I changed my throttle cable about a month ago because it had a tight spot where I'd have to hit ...

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    Throttle sticking (not the cable)


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    I changed my throttle cable about a month ago because it had a tight spot where I'd have to hit the pedal hard to get past it. It's been fine since then until about three days ago.

    I noticed when I push the pedal more than half way down and release it, it hangs up for a couple seconds before the RPMs go down. The pedal does come right back up smoothly though. So today I pulled the air cleaner off and worked the throttle from there.
    Sure enough, I rev it half way, and push the butterfly's all the way back to make sure it isn't the cable, and it stays reved up for a couple seconds. It also makes a weird whiny noise. I ran what was left in a can of throttle body cleaner I had through it to no avail. Should I run more cleaner through it or is something else up here?

  2. #2
    Registered User dave89iroc's Avatar
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    Re: Throttle sticking (not the cable)

    remove it from the truck, and clean in really good inside with carb clean and an old toothbrush
    ASE Master Certified Technician

    2000 Silverado 6.0 4L80E 2wd
    *RIP*1994 Z71 SCLB 355, Dart Heads, 10.5:1 CR, PM rods, CC XR270HR

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    TK TLKurtz's Avatar
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    Re: Throttle sticking (not the cable)

    The GM throttle bodys seemed to have a problem with building up gunk. I've always used the thick blue disposable towels, doused it with carb & choke cleaner, opened the butterfly with one hand and stuck the towel into the throttle body as far as possible and cleaned it. This has always worked for me, but as stated if you are still having a problem you may need to remove and clean it.
    -TK
    TLKurtz
    2014 Chevy Silverado Z71
    2005 GMC 2500HD ECSB - SOLD: 03/13/2008

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    Re: Throttle sticking (not the cable)

    Well I sprayed it out with throttle body cleaner without removing it and that took care of the throttle body sticking problem.
    I also noticed I pulled 7mpg on that tank of gas, normally I get 11 which is low to begin with. I'm hoping the dirty throttle body was the cause, and I'll get back up to at least 11. Unfortunately I was out plowing a couple days ago so my MPG numbers are going to be off on this tank.
    Last edited by RiceKill; 12-16-2007 at 10:14 AM.

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    Re: Throttle sticking (not the cable)

    Well the problem is back and came with an additional one. She just started running really rough the day after the problem came back.

    As far as running rough and lousy gas mileage goes I found a spark plug wire burnt through so I got all new plugs and wires. That helped a lot. Then I found my knock sensor is shot. I replaced it and a new harness is on order. That helped a lot more.

    I still have the sticking throttle problem so I removed the throttle body and cleaned the heck out of it with throttle body cleaner. It really wasn't too horrible inside. I sprayed out all the passages and such until I got clean cleaner out of them. I then re-installed it with a new gasket and silicon. It's still doing the sticking game. I'm out of ideas here.
    Last edited by RiceKill; 12-29-2007 at 05:14 PM.

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    Re: Throttle sticking (not the cable)

    I just finished mine today. All went very well. Mine was so bad with gunk. Fine works great now....on to yours:

    1. Did you remove your TPS sensor and IAC? there's a bearing in there too. I was real careful that I didn't get carb cleaner on the bearing. I think it's sealed, but I still wanted to be careful.

    There's a TSB out about the older TB. IF your vehicle is a 99 or a early 2000 you might want to check it out. The TSB is 00-06-04-007A. Check it out. You will have to take your TB back off to inspect the julian date to see if you have the defective TB. Let us know if you need further help.

    BTW, put your year and model of your truck in your sig so we can help answer your questions better - thanks.
    Last edited by RedStinger; 12-29-2007 at 06:38 PM.
    2000 Z71 Extended Cab
    182,000 Maroon and Silver

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    Re: Throttle sticking (not the cable)

    I had a sticky throttle problem such as yours and mine ended up being the throttle shaft bushings were wore so bad the butterflies would stick in the throttle bore when the engine was running. With the engine off and no vacuum pulling on the throttle shaft it would operate smoothly.
    1991 k1500 ext cab,355,flat tops,L98 heads,lt4 roller,thorley headers,edelbrock intake,bored throttle body.

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    Re: Throttle sticking (not the cable)

    It's a 1990 K2500 305tbi

    RedStinger
    I always add that when I post, it just slipped my mind. Anyway I did remove those sensors. I found one of the bolts for the TPS has the head snapped off. That shouldn't hurt anything though so I just left it that way. The IAC I removed and hosed off with throttle body cleaner. I'm pretty sure it isn't going to hurt it.


    91nitro
    It was doing it even when I physically forced the butterflies closed and visually verified they were closed.



    I found the problem. I left a vacuum hose off the back of the throttle body. Now it works better (except for the new problem I'll get to in a second). I'll bet it was a vacuum leak between the throttle body and intake manifold causing the problem in the first place.

    Now however my throttle cable really is sticking for some reason. I just can't win with this thing. Oh well, that's not too hard to remedy.

  9. #9
    Registered User chevy6490's Avatar
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    Re: Throttle sticking (not the cable)

    They have had problems with those throttle bodies, you will need a updated replacement for it which has a new anti stick coating on the blade that wont wear off. Had the same problem with the one on my truck
    2008 Silverado Z71 Max, L76 6.0, 4L70E, 14bolt Rear, BlackBear AutoCal, Intake, Actuated Strait Pipe, Leveled, LineX, Detroit TruTrac

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    Re: Throttle sticking (not the cable)

    How much did the replacement throttle body cost?

  11. #11
    Registered User chevy6490's Avatar
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    Re: Throttle sticking (not the cable)

    3 or 4 hundred I believe. You can probably find one online for cheaper. I would go talk to your dealer about it and see if they can order it otherwise.
    Last edited by chevy6490; 04-11-2008 at 12:57 PM.
    2008 Silverado Z71 Max, L76 6.0, 4L70E, 14bolt Rear, BlackBear AutoCal, Intake, Actuated Strait Pipe, Leveled, LineX, Detroit TruTrac

 

 

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