SCT3015 beginner

Laurence Dunn

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My car was a bit hesitant on acceleration, it felt overfueled or underfueled, not sure which and the rear O2 sensors had lit up the CEL for the last year.

So I got an ancient SCT3015 X3 tuner unmarried, plugged it in and went into the menu, it must have downloaded my stock tune ok. For some reason I could not find any canned tunes on the device, I followed the brochure instructions, maybe they were deleted by the previous owner. It recognised my Mustang 4.6. So I had a play and managed to switch off the rear O2 sensors. Then as I could not locate the canned tunes I did a revert to stock tune, uploaded it. I then checked the rear O2 sensor status again and it said they were back on, but no CEL this time.

The engine is in good shape, new throttle body, injectors, plugs, coil packs etc.

Well the difference to my Mustang seems to be amazing, the engine runs so much better and now pulls like a train. What happened here? Divine intervention?
 
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Forty61

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I'm sure more knowledgeable people will chime in but if you essentially went back to where you were before and noticed a difference the only thing I can think of that would have changed would be any adaptations the ECU had made over time. Reflashing doesn't fix codes, just erases them, so it may come back in time.
 
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