Hey guys! Or gals. I bought a 2008 G8 base V6.it seems to be stock except for cold air intake, exhaust sounds non stock but not sure. When I get on it hard and it reaches almost 6k rpm, it starts skipping and the check engine flashes and misfires. But when you turn off the engine then restart, it's back to normal without engine light or anything until I do it again. I got multiple random p300 codes from my cheap scanner so I replaced the coil packs but it still happens. Any ideas?