losing ingnition at 4500rpm

hi there we have put a link g4x into a cobra kit car running a ford 5 litre fuel injected motor

having a issue when it hits 4500 rpm it back fires and seems to lose signal out of the back of the ecu to the ingniton box, tacho drops to zero, but car will keep running and run perfect until 4500 rpm

not sure if its in the tune or a fault with the ecu

data does not drop out at this rev point from ecu

any help would be great

thanks

Could this be a rev-limiter safety that kicks in if the coolant or oil temp is too low? Does your ECU logging include any diagnostic or status channels that might indicate what has happened?

Attach the tune and a log of the problem.