i have an injen cai and i just installed my PG test pipe today and when i shift from first to second and second to third at peak power, it stumbles for a second and then boosts fine. is this normal? my friend said its because i'm giving it too much gas and not all of it is burning... if i shift at peak power and wait a second before i go wot, it boosts fine with no stumble... i wonder what i can do to help this? octane booster? i've read about people talking about this before. thanks for any advice in advance guys! btw, i can definitely feel the difference with the test pipe. and the exhaust sounds deeper. beautiful.