whats up fellas! I have a scion xa 06 auto. it is equipped with a injen CAI, DC headers, light wieght pulley, exaust, bigger catalytic converter, 3" piping from headers to exaust, iridium spark plugs. After all this it feels like I lost power!?!?!?!.....i have a a very slow start/rough (gas pedal is hard/heavy) after a couple of seconds it seems like it catches up with it self...wierd! any suggestions ! I want to fix this before going (TC or SC) ...

 

its probly cause you did lose power...oversized piping.. 2-2 1/4 is "perfect" for n/a. idk if 3" is to big or not wit FI.. search and destroy my friend

 

yah. you lose power opening up the exhaust to much.. you lose all the backpressure (torque) hard for a car to move without this..

 

I was trying to figure it out....good to know...so I will adjust that...do you think i should go catback