Hrmm...have you filled up since the install. Reason I ask is because My truck was doing the same thing after I got bad gas (water in the gas) one time but it knocked out a purge soleniod or some thing like that. They replace the purge hose and cleaned the injectors and viola no more problems. I think water got trapped in the fuel rail or something. Mine would do it randomly though and I'd get mad and punch it and it would sputter and buck like a mule then take off like a bat outta hell when it finally cleared, usually in a couple of secs...