I have no check engine light and the car really pulls through the rpms, but the mileage is crappy, 15 mph, and it feels really weak right off idle. The only mod is a cold air induction. When I first give it gas to move when I start the car, it hesitates, then dips in rpm, and then lunges forward likes it catching up. Its an auto by the way. This is usually when I tap the gas to get it rolling like when backing out of a parking space. The rest of the time its fine but it still feels sluggish all the time like its not trying. Car has 107,000 miles.