I just got this car, i know very little about it, it has the whipple 2.3, iridium plugs (brand unknown), but when i did a 4th gear pull on the highway, at about 90mph the car backfired rapidly (about 6 times), and a plume of black smoke (i assume unburn fuel) was left in my trail, my battery and check engine light came on, but within 10 seconds were gone. Car now comes to stops with a high idle, then eventually the idle will come down and it will kind of run rough. Is this plug blowout? I'm going to pull them tomorrow to see what they look like, but i'm kind of alarmed.