Brief history of my WRX. I bought it back in FEB 2011, it appeared to be well maintained when I took over. It would backfire when the clutch was in to change gears and there was a constant very faint smell of gas in the exhaust. It had about 75k on the odometer. So with all that I thought a good thing to do would be to replace the plugs.
Mods on car: 3" turbo back exhaust, cobb "cold" air intake, big k&n filter, probably some type of Accessport map loaded - cobb usb adapter thing was on OBD-II port when I bought the car.
Ok so changed out some NKG PFR6Gs (double PLT) with some NKG BKR6EIXs (iridium).
The old ones came out, looked dirty/oil around the threads and discolored around the ground electrode. Gap on old plugs was between .032 and .035
I checked the gap on the new plugs and it averaged .026. I read on here and other sites the gap was supposed to be between .028 and .031. I gapped the iridiums to .029. And yes I did so very carefully as to not damage the gap surfaces.
My problem seem to be my MPGs took a big hit. I was getting just shy of 300 miles to the tank and now its around 250 miles. I just though of something, might have answered my own question/problem. I have been driving it more spirited-like and it has been hot as youKNOWwhat around here so the A/C has been on a lot.
My questions are: does my spark plug change sound like it would be dropping my MPG?
is it possible to tweak a cobb map to were you would have to gap your plugs differently?
when is this stupid southern heat wave gunna end?
thanks for your time...