What is a A9L & A9P Computer?
The A9L Fox Body Mustang computer is found in 1989-1993 5 liter-manual transmission equipped Fox Body Mustangs and the A9P was found in automatic equipped 87-93 5.0L Fox Bodys. This is suppose to be best performing, most aggressive (mass air) processor used by Ford. If you are doing a mass air conversion you will need to replace your mustang's computer with an A9L or A9P depending on your transmission.
What Makes these A9L & A9P Computers so Sought After and Hard to Find?
Finding these computers can be a task in itself. Ford has discontinued the production of the A9L and the A9P. Now these computers are being refurbished for the Fox owner looking to swap to mass air. If you are lucky enough to find one, be prepared to spend a pretty penny.
Conclusion
Using the A9L or A9P computer for a mass air conversion is the quickest and easiest way to get your Fox back on the road. However, locating one of the rare computers will be part of the journey. We hope this little bit of information helps when trying to figure out why you might need a A9L or A9P computer.