Hey guys I bought a cheap header off of ebay and its the aftermarket ones like this http://www.ebay.com/itm/STAINLESS-RACING-H...HAo&vxp=mtr , the reason why I ask is cause I redid the motor and bought a ton of new parts but now I have performance issue, I have really bad power till i hit 3.5-4k rpm which is really not ideal. and im thinking maybe its cause the header has the o2 sensor is only using air fuel ration from 2 cylinders instead of all 4 cylinders? does anyone have information on this? sorry guys im just trying to narrow down things is all, i'd like to get down to the bottom of my performance issue. im only getting 22mpg.
Header on 7AFE cause performance issues? - 6G Celicas Forums
Timing may be off a tooth on the timing belt, double check that. I had that header on my 7A a long time ago and I had nothing but improved performance.
2000 Celica GTS 'slowest gts evar'1998 Mazda 626 FS-DE/CD4-E
>
Ok great thank you! Glad to hear that it doesnt affect performance in a negative way! I'll check the timing.
QUOTE (Bitter @ Apr 30, 2016 - 2:31 PM) 
>Timing may be off a tooth on the timing belt, double check that. I had that header on my 7A a long time ago and I had nothing but improved performance.
Ok great thank you! Glad to hear that it doesnt affect performance in a negative way! I'll check the timing.