I recently replaced the engine in a 1999 GT with one from a 2004. The engine I removed had a Kenne Bell, and other supporting mods, and a custom tune is on the computer. The car won't start and remain running. It sounds as if the timing is too far outta whack. The 04 engine is bone stock. I have checked all the usual suspects, Crank & cam sensors, gem, CCR, etc. The only remaining mod on the car now is a 325 Aeromotive fuel pump. Now, I am aware of the PATS...could I upload a stock tune file with an SCT tuner, and not interfere with the key programming? I have also read that Ford changed the platform, or operating system of later models like the 04. So is attempting this with a 99 computer a waste of time? I've attached a photo of the label on my stock 99 computer. Appreciate any insights! Thanks!