He didn't say, you look up his profile?? Oh well I dunno I still think these guys are retards. Fuel control isn't based off the secondary O2, Oxygen sensors don't really look for oxygen so putting it in a plastic bottle isn't going to do anything. I wouldn't call it a modification.. it probably went to default fuel control look up tables and these assclowns think they're "tuners" now and it's now a "modification". ppl need to get educated about cars before they post on here, I'm getting tired mmust sleep