Need helo figuring out a/f ratio

[Manny974v]

I have a 1997 mustang gt with a 97 cobra swap the whole motor is stock ither then having a full off road xpipe no cats a and full catback and the air fuel ratio sits at 17.0 to even 17.5 sometimes when I drive it flashes red what would the cause be

 

[wmburns]

What are the long term fuel trims (LTFT)?

What are the MAF flow at idle and 2000 RRM's?

What is the fuel pressure at idle? At 2000 RPM's?

Is there an exhaust leak between the heads and the AF sensor? IF so this will make the AF read lean.

Basically what I think should be done is to confirm IF the AF as reported by the wide band senor is reasonable or not by cross checking against the LTFT's.

ForScan ODB2 scanner w ELM327 USB

ForScan ODB2 scanner w ELM327 USB

While working on your car have you ever wanted: to find an ODB2 operational PID value (say fuel pressure or MAF)? How about graph a PID value over time? Or compare multiple PID's over time? Access a bi-directional PCM control such as test a...

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