mine was nice and clean on the outside too, flip it open, spray some carb cleaner in there. remove the maf if its in the tb, never spray anything on a maf but maf cleaner. ( or you'll kill the maf) then get your old tooth brush and scrub around, it will come out black as night.
i respectfully disagree with the maf cleaner. i have used electrical contact cleaner multiple times for the MAF. no big deal though.
1997 Grand prix GT Black Coupe- The beater
1998 Grand prix GT Black coupe- Top swapped, XP cam
2008 Grand prix Midnight blue- The slow but nice car
1999 Chevrolet Silverado red ext. Cab