I recently had the throttle body cleaned on my 1995 3800 SC Bonneville. It idled perfect before the work was done but now it revs up for a few seconds and then barely idles after that. I have replaced the Idle Air valve and the Egr valve and know difference. I have checked for vacuum leaks and found none. The engine code has always showed bad Egr valve for last few years but have replaced that twice. The engine does not respond as it should but runs fair.
There must have been something damaged when the garage removed the throttle body for cleaning.

Check for vacuum leaks. Also check the EGR tube between the EGR valve and the lower intake for cracks.

I did find a crack in the EGR tube earlier which I sealed. Seamed to help a little but then it almost seems like it got worse again. I am going to re-check all lines again. Thanks

Also on the Supercharged engine there is a tube from EGR to throttle body and a tube below EGR to exhaust manifold. I do have a exhaust leak but was told that would not affect idle.

Any leak should be taken care of. I would recheck that EGR tube. How did you seal it? Only a new tube will truly fix it.