88 1500 5.0 throttle sticking closed

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Greg S Meier

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I have an 88 305(5.0) all stock.
The throttle sticks closed only when running. Turned off no problem. I unhooked the cable & it's free & not hanging up on the plastic sheild.
Not running I can move the throttle easily (cable unhooked)
Running, it sticks (cable unhooked).
You can't start from a dead stop w/o pealing out.
HELP
 

someotherguy

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Pretty weird symptoms.. however: if you have cruise, try disconnecting the cruise cable at the throttle body. Sometimes (rarely) the cruise unit goes bad and can cause issues.

Richard
 

Greg S Meier

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Pretty weird symptoms.. however: if you have cruise, try disconnecting the cruise cable at the throttle body. Sometimes (rarely) the cruise unit goes bad and can cause issues.

Richard
No cruise.
I'm atta complete loss!
I lubed everything.
Ugh
 

PlayingWithTBI

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Sounds like your throttle blades are sticking under vacuum. Check to see if there's any slop in the throttle bar bushings. Maybe even screw in the idle min stop screw (T25 IIRC) a tad to prevent them from jamming?
 

Greg S Meier

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Will
Sounds like your throttle blades are sticking under vacuum. Check to see if there's any slop in the throttle bar bushings. Maybe even screw in the idle min stop screw (T25 IIRC) a tad to prevent them from jamming?
I will try it! Is there an aftermarket thing I could replace the thing with? Not Holly. Would be looking for better mileage if possible
 

thinger2

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Wait a sec. You cant stop it from peeling out with the throttle stuck closed?
Did you mean stuck open?
I didnt bother looking at all the info cuz Im just lazy so,
Is this a carbed engine?
If it is (and sometimes even with TBI)
You might have a broken motor mount.
Torque twists the engine and pulls the throttle wide open.
Check it out.
It can be real dangerous
 

Greg S Meier

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Wait a sec. You cant stop it from peeling out with the throttle stuck closed?
Did you mean stuck open?
I didnt bother looking at all the info cuz Im just lazy so,
Is this a carbed engine?
If it is (and sometimes even with TBI)
You might have a broken motor mount.
Torque twists the engine and pulls the throttle wide open.
Check it out.
It can be real dangerous
Yes. Peeling out. You have to push the throttle pedal so hard that when it does cut loose, it peels out.
It's not carbureted. Its tpi. No broken motor mounts. It sticks closed not open
 

Greg S Meier

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I'm very experienced w broken motor mounts.
My Pontiac 388 w tri power would brake driver side & rear motor mounts regularly. It would cause the throttle linkage to get stuck with the trans kickdown linkage. Wide open!
Quite the thrill!
 

Schurkey

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As said, likely the throttle shaft "bushings" are worn. The throttle plates aren't precisely located any more, so they jam against the side of the throttle bores.

Find another TBI unit, install, see what happens. You'd want a TBI from the same year and same displacement for easiest swapping--although it's not too bad to mix model years if you know what you're doing. Swapping displacements from V6 or a 5.7L is trickier as you'd need to re-use your injectors.
 
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