My 87 TR was getting terrible mileage on the hwy, like 10 mpg. Replaced the fuel filter and mileage went back up. I just got 21 mpg on city/hwy combo (90 miles city and 90 miles hwy). I usually get 15 mpg city, so maybe city has increased a little. Car only has K&N and stretched intercooler. Stock cam, injectors, turbo, transmission, Full Throttle chip.