I can tell you what is wrong with your seat maybe. More than likely one of the three elements in the seat has gone bad( little over a hundred bucks if you can do it your self, my dealer quoted me just under five hundred w/ labor). Is a stuffed cat that common? sure seems to be a common first diagnosis. If I were you, first get the car scanned, that would be the most helpfull for everyone here. Being at 93,000mi you're only 7,000mi from GMs' recomended tune up, I'd just do it now if possible(your dealer wouldn't do any more than what is absolutly necessary, their objective is to get the most $$$ out of you). Also check your tranny fluid w/ the car running (color, odor and level would be helpfull info as well)
Gutted air box, K&N drop in, MAF screen put back in , NGK tr-55 @ .55, 180* drilled t-stat, INTENSE 3.4mps, Aeroforce, High-flow cat, and one BIG F-ing smile.