[Regulator]

It seems Motorcraft lists a different coil pack number (DG512) for the 99 Mustang only, but the 00+ all have DG508. Do I HAVE to use the part number specific to my car or can I run the other part number without issues?

Also, is it best to stick with stock OEM coil packs or are any of the aftermarket versions good to use? I know when they first came out there was a lot of discussion about them going bad really fast, I didn't know if that was just a specific brand or if they are all like that.

[casper gt]

Ive ran into some strange 1 year only stuff for 2000 also. IMO, I'd use pretty much any year coil-pack with out a second thought, but I have ACCEL coils on mine not with no complaints.

[Regulator]

Well after a lot of research today I found that it has to be year specific on the coil packs, the wiring harness connector accepts a thinner prong than is on the 00+ so if you try that it will probably mess some stuff up. I had a friend come through on a spare one and it seems to have cured the issue, but before I swapped them out it threw a code for the coil pack that sits right next to the coil pack that I knew was going bad. After I swapped out the known bad coil, it runs great again and haven't gotten any more CEL's.

Could that second CEL for the other coil pack have just been a fluke?

[casper gt]

while I havent had the problem my self (knock on wood ) you may be staring to have that coil wiring problem that comes up on here occasionaly. cant quite remember exactly the problem but it has something to do with the wire insulation deteriorating in the loom & causing random coil problem's much like your describing (code's coming & going for no reason, along with driveablity issues) & eventually the car just wouln't start. mabie do a search on something like "coil wiring" or something like that.