Mechanical Problems & Technical Chat
I have a 2009 civic EX (A/T with 173k miles). No mods (I did remove a shim from behind the AC Clutch to make it work, which it does so now). My cars mpg seems to be decreasing over time. I was getting ~35 mpg a year ago on the highway, now I get about 29 mpg.
The spark plugs were...