thread hi-jack:

is a 02 sensor still needed on a ej20 running a aftermarket ecu (ie possumLink ecu)?
reason i ask is because i have apexi turbo timer with a functioning air/fuel ratio meter on it and lately i have noticed the a/f ratio readings are all over the shop on light throttle (ie sometimes is will read up to 20:1, then jump up and down, only on light throttle)

i believe that the turbo timer gets its a/f readings from the o2 sensor, so am i right to think that these erratic readings are due to a faulty o2 sensor?