if you are just having throttle lag, which is very noticeable on manual transmission, I recommend using the Sprint Booster product. I've installed it on my 07 2.4L stick shift and no more lag works great! Down shift throttle matching is right on and no more sloppy up shifts. It changes throttle response TIME it's not a performance enhancer. Some folks out there say they'll just push the pedal farther down,that might work on an automatic or turbocharged car but this is a matter of response. Of course run a diagnostic test for trouble codes, a sticky throttle body, bad sensors ,or a faulty catalytic converter can really gum up the works. Good luck.