I've got a 98.5 A4Q 2.8 car with 95k miles on it. It runs great, smooth, more-or-less quietly, and with normal acceleration, but in the last 3 tanks of gas, its mileage has dropped from its usual 22-24 mpg down to 18-19 mpg. What should I be looking for as the culprit?
This mileage drop started during warm weather (40s), so I can't blame it on cold temps, and my tires are inflated properly. The car is a MT, also, but I'm the only driver for the most part. Suggestions?