Is there any way that you can tighten the throttle return springs on the throttle body? I have a stock 86 IROC with a 305 TPI. The throttle will come back to within 1/8" of the stop, intermitantly. Sometimes it will come all of the way back, or you can manually push it back. Any ideas? Is it possible to tighten the spring, or that the bushings?berarings are going bad?

 

BHull,

Your throttle shaft has bushings. Tightening the return sprnig will only wear them out faster. You should disconnect the throttle cables (up to three of them if you have cruise control) and see if the throttle still sticks or returns smoothly. The you find a sticky cable, replace it before it sticks enough to put you into a tree or parked car.

If the throttle sticks without the cables attached, you should first clean it thoroughly, then lightly lubricate the shaft bushings. Keep any oil away from the TPS unless you planned to replace it anyway. If cleaning and lubricating the TB doesn't repair the problem, check teh throttle plate alignment. If you see signs of the edges of the throttle plates polishing the bores, they are probably not centered. This is usually due to bushing/shaft wear, but can be from mishandling. You may be able to completely back off the throttle stop screw, loosen teh throttle plate screws on the throttle shaft, and realign the plates so they close without interference and binding.

Chances are, if the plates are sticking, you need to replace the TB sooner or later. Hopefully, you only have a cable going bad - they're a little cheaper.

 

You can buy a throttle return spring (intended for carbs). They usually come as a double spring but using one will be sufficient. I had the same problem on an 86 tpi and that worked perfectly.

 

Thanks everyone! I found that the bracket that the throttle/tv cables run through was bolted too far back on the upper intake, causing the throttle cable to pull on the the linkage. I just loosened the bracket, pushed it forward and re-tightened. Thanks!