I know this has been covered a lot, but when I searched I saw everyone suggesting to replace plugs/wires/fuel filter/02/etc...
Basically, I'm only getting around 21mpg no matter how I drive. I believe the most I've gotten out of a tank of gas is 280 miles, and that was 90% freeway.
I've replaced the plugs, wires, fuel filter, 02 sensor, air filter (CAI), oil, tranny fluid (though i dont see what difference this would make) and they have not helped my gas mileage at all. I have a test pipe on this car but I know that wouldn't affect anything since the 02 is in the engine bay. Sometimes it gets so bad that when I come to a stop I can smell the gas. I replaced the stock cat with a test pipe hoping it would help my gas mileage.
Anyone have any ideas? When I got my car smogged they saw the timing was off so they adjusted it for me, and I passed smog with almost perfectly neutral numbers (when I had the cat on, of course)
Car has 105k on it.