i dont drive my truck much in the winter and when i do if i let off the gas completely then press it it sticks some. i thought it was freezing up some seeing as my 90mm tb doesnt have a the radiator fluid hook up like factory does.

well last night i changed my oil and was looking more into this sticking. it feels like it has a super strong vacumn that keeps the tb closed. then i have to break it loose.

anyone know what would cause this?

 

I have seen this many times on the cable operated throttle bodies 99% of the time its carbon around the throttle plate. Remove intake get a toothbrush and some brake clean open the throttle by hand and brush all of the carbon away and then spray it out. Its ok to get some cleaner in the intake. This should fix your problem if it doesnt the throttle body may have slop in it causing it to hang but its likely the carbon. hope this helps

 

Does it do it when the truck is off?

 

nope doesnt do it when its off.

the motor is sucking the tb closed. at idle i have 15 whatever you call it of vacumn according to my boost/vacumn gauge. its hard to explain. but feels like a sticky carbon build up tb but its the motor sucking it shut.

 

old bbk t.bodies used to do that.
they didn't have the small vent hole in the throttle plate that the factory plate did,
hence high initial vacuum until the plate unseats.
haven't looked recently to see if oe plate still has the hole but you may be able to drill a very small whole in the plate it you don't find any other solution.

 

I don't see how the design of the throttle plate would allow it to be sucked shut...

That vacuum force should balance out, no? Half of the throttle plate is aided by vacuum, the other half hindered. Unless there is some offset.