Hotsauce101

iTrader: (4)

So a few nights ago my CEL came on... p0134. Was odd since that o2 sensor had less than 20k miles on it. It also came on when I filled up at a station I never fill up E85 on. Also noticed that when I am cruising my AEM wideband pegs 10-11 AFR's for 1-2 seconds then goes back to 14.7ish. I don't feel any hesitation when this transition happens. Also tried WOT a few times and it was pegged at 10 on spool up (3600-4200 RPMS).

My first guess was a bad O2 sensor. So i used one of my old ones and 40-50 miles later it came back. Bought a brand new Denso one and it came back after 40 miles. I tried to run the current tank empty to try to fill up at my regular E85 station. The tank was 1/4 so I topped it off with E85 at my regular E85 station. It seemed to get better..... noticed the rich spike to happen less, but it was still there. Is this the symptoms of bad batch of E85???

Drove it to work today and saw it spike a few times. On my way home it didn't????

Any one have any suggestions???