First off, I'm not looking for power. This is a daily driver and I just want the most MPG possible.

The engine is all stock except for a K&N air filter and I do oil changes very regularly.


I was talking to some people and some say that the fuel pump puts out more than enough pressure at all times so unless the filter is really clogged, a new one won't do anything. I tend to agree with them.

Others say that the fuel pump has to work harder with even a slightly dirty filter and this would lower my MPG because of a bigger electrical load.


My car starts and runs fine all the time. Doesn't show any symptoms of a dirty fuel filter. From what I've seen with past cars, fuel pressure was always the same(idle or redline) in the line. So going by that, I would figure the filter wouldn't affect the MPG unless of course its super clogged and then the engine would run like crap or not run.


So which one is it? I've only encountered a clogged fuel filter once and that was with a really old car that was sitting forever. I do everything possible to keep my car running good but I don't like buying things I don't need and fixing things that don't need to be fixed.

 

It should be done as maintenance anyway. If it was never done I would do it, it is about 20 bucks. As for mileage I doubt it help, unless it was really clogged and you would know it. Any after market high flow fuel pump kills mileage.

 

I've never noticed an increase in MPG from just a fuel filter. Keep all your fluids fresh/clean as you do your oil. Less friction=more MPG. The K&N helps but a CAI will further improve MPG.

 

Better fuel flow = more power = less need to rev higher it to get it to move
It DOES indirectly affect MPG
^^