I was using a SCT chip that had multiple positions. I only used 2 of them. 1 was for pump gas, the other was a race fuel tune. Seemed to work ok... Mine had a little cord with a multi position dial.
I was told to NEVER turn the knob unless the key was in the off position. That's all I remember really. It was on an A9P for a 92-ish fox.
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General Stonewall Jackson has been quoted saying that when the time of war comes,
“My advice is to draw the sword and throw away the scabbard".