SR8993

A dirty filter does indeed effect your mpg. If you have a MAF and it isn't getting the reading it wants because it is air restricted, the system provides less fuel. Then when that gets back to the Oxygen sensors lean, they are telling the system to add more fuel. At this point the entire system is battling itself trying to keep things within parameter. So that, vs a clean filter not hindering your sensed A/F ratios...... you're telling me it doesn't make a difference?