I Finally got my ride back yesterday from the shop. it got a vortech s trim. but it is still running the stock mass air meter. The tuner told me not to rev it over 4800-5000 rpms cuz it runs way too lean above that due to the stock MAF. So i just took it out to race a guy and i was shiftin through the gears really fast around 4800. when i went from 3rd to 4th a huge cloud of smoke flew up behind me and came all through my vents. the whole interior was smoked out. then the car backfired, not too loud, and shut off! we raced again about 5 minutes later and it did the same thing. any ideas what is going on?