yeah, been there done that, but half of the customers don't know shit (not saying you at all) and insist on somethings being wrong with their vehicle and insist they have a new 5k motor installed because they never changed their oil.
we say "no". this is why alot of dealers get a bad name.
but in all honesty, it seems like what you dealt with was a lazy *** tech that just doesnt give a fuk anymore because GM is already cutting more and more pay everyday. Plus, he's probably out of the loop due to hybrids coming out and 32v type things coming out. I have already learned more that the avg. tech out there knows about programming, electrical, modules, ect.
Not just a simple carb tune, or a adj and let er go. Its crazy these days.
Every ****in thing on a vehicle has a module hehe.
BTW: Your GTO is sexy.