Mustang#2

It sounds like you are flooding the chambers. Your pulling spark, but still adding fuel. I can see why this is happening, but on my previos mustang (4.6) I had the DIS4 which had that same function and it never did that it worked great.

1990mustanggt

I'm at a lose on it. It just keeps on backfiring when I use the module. I'm going to take it out and drive it Wednesday night and then pull the plugs and see what's going on with it.