Joined: May 2014

Posts: 341

Likes: 10

From: Florida

Hey guys,

My front O2 sensor has gone bad again for the third time in 3 years. Each time I replaced it with a brand new one (denso I believe). It always starts with the CEL for bank too lean.

Any ideas as to why this keeps happening? 06 MR with E85 and bolt ons.

Joined: May 2008

Posts: 7,704

Likes: 1,387

From: So.Cal

Joined: May 2014

Posts: 341

Likes: 10

From: Florida

none of those 3 on my car, but I will check to see if that can be the culprit from something else.

Joined: Nov 2004

Posts: 1,459

Likes: 110

From: Chattanooga, TN

Joined: Jun 2006

Posts: 6,902

Likes: 151

From: Grand Island, NE

Joined: Sep 2007

Posts: 328

Likes: 23

From: NJ

This is most likely your issue. Once you mod and start running 🌽 added heat and rich conditions over time just foul out the sensor.

Joined: May 2014

Posts: 341

Likes: 10

From: Florida

Niether according to the AEM gauge until now. Since the CEL it’s been running rich to compensate for the bad O2 sensor. At least that’s the way I understand it.

Joined: May 2014

Posts: 341

Likes: 10

From: Florida

Each of the past two times was different sources but maybe I’m just unlucky lol

Joined: May 2014

Posts: 341

Likes: 10

From: Florida

is there a specific sensor that would be able to withstand E85 better?

Joined: Sep 2007

Posts: 328

Likes: 23

From: NJ

Not to my knowledge. I always keep one on hand Incase it goes bad because the car will run like crap. You can get them cheap from rock auto and they are true denso sensors.