Good morning/afternoon,
New member here. I don't actually "own" a Grand Prix but my girlfriend has a 2008 SE with the Series III. Very nice car, and fairly solid. It does have a few wiggles that I need to straighten out for her thus my reason for joining. She had been using a local "mechanic" and he presented her with a list of ~$2500 in "repairs" the car needs. None of these address the main concern I have which is the "reduced engine power" warning she has had on and off for 3-4 years (we have only been dating 6 weeks). Well this popped up again and she called me late one night in a panic. So, that is the first issue to address. I think I have a handle on it (TPS related, in the gas pedal or throttle body) and last night I read the codes and gave it a quick once over. Once I sort that issue I planned on giving it a complete maintenance treatment. It only has 172K miles on it and obviously has the wonderful 3.8l V6 so it still had a lot of life left in it.
A bit about me; I am a mechanical engineer and work for company that designs thermal management systems for diesel engines. I have owned quite a variation of vehicles but prefer a few specific makes (Chevrolet, Pontiac, Toyota, Honda, and Packard). My current "fleet" encompasses a '93 K3500 that has been in the family since it was new, 2013 GMC Sierra, 2015 Malibu, 2016 Toyota Tacoma and now an adopted 2008 Grand Prix. I do all my own work and for the most part am not afraid to try and fix anything.