gmantwo
Full Member
So, I bought my first, but definetely not my last, Avalanche. '07 LT T3, 133,000 miles. Installed new Iridium plugs, MSD wires and a K&N cold air intake. My gas mileage went from 15.9 to the high 13's low 14's range. WTH??. Anyone else have any experience like this?