Re: ITB Conversion on 16 valve 4AGE On my inventory bigport AW11 a leaking exhaust manifold gasket caused the O2 sensor to read through lean and it pumped gasoline into the motor. Fuel financial system plummeted until I sorted it out. BigAl wrote:Just what the hell is often a BTDC? https://4age-20v-itbs37935.isblog.net/what-does-4age-20v-itb-mean-51778923