I have an EF Fairmont 6cylinder and it has a surge that happens randomly every now and then.Your driving along and just out of the blue it will surge on and off for about 30 seconds then run perfectly then ranomly do the surge again.Sometimes at stop signs it is like its going to cut out but hasn't fully cut out yet,so far ive changed:

coil pack
plugs and leads

ideas.

Had the same problem last year on my ED.
The surges and sudden motor cut outs culminated in an explosion that blew my exhaust apart. Before there was a serious misfire out of the air filter!

The problem was the TFI module. Before you replace the TFI module disconnect the harness and clean it well, scratching each contact. Don't damage them!