[bobcowan]

The Mas-Flo system uses most stock Ford parts. There are a lot of advantages to that. The disadvantage is that the stock A9l computer can only go so far. Most Mustang guys know that if you do anything more than simple bolts on's, the stock ECU needs to be tuned. And, it does very little self tuning. Only within the parameters of the Stock Mustang.

If you've installed anything more than the bone stock Mustang 5.0, you need a tube.

There are a couple of tuners for the A9l, and they all have their followers. Find a local tuner who is familiar with what you have, and then buy whatever tuning system he recommends.

If you do have a b one stock 5.0, and the stock ECU won;t run correctly, there's a problem in the system. It should run well without spending much money on it. Any codes? check for vacuum leaks, loose wires, bad grounds on sensors. etc.

Maybe you can take it to a local Ford dealer, and have them hook up their computer for a diagnostic check.

There's probably no reason for you to spend $3,000 on a new ECU, when you probably have a perfectly good one already installed.