What computer is this?

A9L and A9P are the two "best" Mustang computers. They are the most aggressive factory EEC's in a MAss Air car. The A9L is a 5-spd and the A9P is an AOD computer.

The A3M is not a 1993 computer. I think that's a C3M1 or something like that

A3M is a 1989 service replacement for a A9L....basically a Ford reconditioned computer

I have a mass air computer from police car - Ford Mustang Forums

vristang said:

'Aggressiveness' is often exagerated, as the ecu differences are pretty minimal. I've never seen back to back track data for different ecu's? Anyone seen this?

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I don't think the differences are worth swapping computers over.

"Aggressive" is a relative term in this case just like 86-88 camshafts were more "aggressive" than 89-later shafts. The actually differences would prob never be detectable on a track or even a dyno perhaps

A custom tune on top of either computer completely negates it so it's a moot point.