Quote Originally Posted by mattstansbury View Post
it happens when your accelerating, it never happens when cruising at 60, even 70..and 80+ means it has happened at 80mph before, but usually its around 90-100 it starts. I gotta work so ill try and pull the plugs when i get back. How much do plugs,wires, and coilpacks cost on these cars? (never had a 3800 befrore) Any sparkplug/heatrange you'd recommend for better performance?
I'd suggest slowing down.

Also wouldn't just start throwing coil packs or anything expensive on the car.

You should give it a solid tune up. That's a given. I'm not convinced that's your problem though if it's only doing it at high speed and no other ranges. It would be a good idea to get a good scan tool (if problems still exist after tune up) and monitoring what's doing what at the point of failure and at normal operation.