Hey guys just wondering what could my causing my 02 GTP to be getting such bad gas mileage. It is all stock has 220k miles but not actual, not sure how many on engine. I am going to do a full tune up soon, plugs, wires, filter, tranny flush, oil change, s/c fluid change. I am averaging 19mpg on the high after 100+ mile trip and about 14 in the city. I was expecting alot better from everything I read before buying. It is throwing 2 codes for shift solenoids which I will be getting replaced soon. Any other ideas on how to fix my bad mpgs?