Quote Originally Posted by Turbocharged400sbc View Post
A few things of note.
From what I can tell you are using the AFR calculation that the computer uses not what a separate wideband is indicating the latter being far more useful than the former.

Also since you are now tuning... some maintenance is in order if your Upstream oxygen sensor has about 50,000 miles or more on it you need to replace it. Those sensors Q overtime and they are a trusted sensor that the PCM assumes is working perfectly even if indicated otherwise.
The AFR calculation that the computer is doing is dependent on what the tune and sensors show it and a dirty and skewed oxygen sensor is about the biggest f****** that could happen in this area.

Stay away from Bosch o2s
Can you rephrase that first part?

I think its a Denso has about 10k on it at most. It switches fine if that matters.