Could A Bad fuel Filter Cause Poor Milage?

[Lubecktech]

I have a 1999 explorer 4.0 V6 OHV which misses on #5 and #6 cylinders (according to the computer) bogs down going up hills and gets really bad mileage. I am getting codes 0174 and sometimes 0171 and can't find any vacuum leaks. I have changed plugs, wires, PCV valve, upper intake gaskets and coil pack. I was thinking about having the injectors cleaned but could a bad fuel filter cause these problems? If it were bad would I be getting poor mileage? I used to get an average of about 20mpg but now get around 14mpg. I will probably get rid of it soon and don't want to spend unnecessary money on it.

 

[J_C]

I'd try (gently) cleaning the MAF sensor with carb cleaner or similar, dirty MAF is a common cause of 0174 and 0171.

If you can get the fuel filter off (not rusted on), it's only a $10 part.

 

[nvfd1127]

i just replaced mine and gained about 2-3 mpgs