the gas mileage in my 99 v6 5 speed has taken a nose dive in the past month or so. It has dropped from ~20 to ~13mpg. the spark plugs look fine, i just put on new tires and and K&N air filter in. Nothing seems to change the mpg. the next thing i am going to replace is the fuel filter and check the timing. however the car is not running rough, it just likes to suck down gas. (and no, i don't drive it extremely hard) the mpg seemed to drop significantly once i got my clutch replaced and has never recovered. Does anybody have any ideas? Please help.
Try cleaning your throttle body and MAF sensor, and run a bottle of Techron through the engine next time you fill up.
I see you have a K&N, definately clean your MAF, I cleaned mine with brake cleaner, K7N is know to gum them up sometimes.
