Re: ITB Conversion on 16 valve 4AGE On my stock bigport AW11 a leaking exhaust manifold gasket brought about the O2 sensor to read lean and it pumped fuel in to the motor. Gas economic climate plummeted until I sorted it out. Thanks very much, i apologize for not clarifying https://4age-20v-itbs03567.blog-a-story.com/15475858/5-simple-statements-about-4age-engine-for-sale-explained