Questions and Answers

GMC Sierra Supercharger Modifications Q. Sir: I have a 1999 GMC Sierra 4.8 liter. I installed a Vortech SuperCharger, works fine, lasts a long time and have no complaints. But enough was not enough, I upgraded the throttle body to a BB&K 80mm throttle body part# 1709. I installed ran the engine to temperature and let the idle set itself good enough.

After running it up the road and while in traffic the accelerator feels stuck and overcoming this bind causes the truck to lurch, works fine in neutral no sticking or friction, feels fine, in "D" it feels stuck. This similar to the GM problem which required a plug and a different PVC valve which I did on the original body.

The engine idles around 600 rpm and goes slightly higher in "D". BB&K will swap the unit out citing previous problems with unven expansion when motor heats up. I suspect something different. And would appreciate any help in either case before I tear it apart. The truck ran well with the original installation.

Thanks,
Chitty

A. All you can really do is try to adjust the throttle plate slightly to see if it's opened a little farther if the sticking will go away. I'd advise against this as the company may need to see it the way it was set originally in case they have others with same complaint.