I think after all my misadventures with tune up and air injection problems gas milage should'v go up back to normal. Well... it didn't. Than a friend sujested that MPG will worsen if you make any air intake or exoust upgrades towards more power. I have a Brulen mufler instoled. Is my friend right? Could the easier flow mufler reduse the MPG?
17" Lorinsers RS90