Ok, so here are specs. '03 envoy, 4.2, 61,500 miles. I just cleaned the TB two days ago, coolant recovery tank was empty, filled to cold, 34% oil life left, always maintained. Brand new tires on all sides. Never had any, flushes, tranny, rad, for the first time i poured gumount fuel injector cleaner when i filled up. Im thinking i need a new fan clutch due to excessive roar noise sometimes when i start and head off. Not everytime, but fairly loud and last about 2 mins. Also, my coolant gauge is 2 clicks away from 210. I just added coolant to the tank, but it still seems at 210. I got the p0128 code so i added antifreeze, hoping it's not the thermostat. Anymore ideas what I can do to gain back my hp, as well as acceleration? Oh, I almost forgot, im only getting 16-16.2 mpg city. Thanks!