do you need a chip when switching to 24lbs injectors.

[69fastback]

I switched my 91 mustang over to 24lb injectors and 73mm mas air (because of nitrous kit I order to go on very soon) now when i turn the timming up to 15 dagrees and step on the gas lots of smoke comes out the tailpipes. It contuines to do this until i trun the timming down to 8 dagrees then the car wont accelarte at all? All i can think of is the computer needs to be update with a chip to match the injectors I don't know though my first EFI car. (I should have stuck with carbs).

Other mobs the car has is cobra intake, cold air, headers, o/r h-pipe and 2 1/2 inch flowmasters. It is an AOD car.

Thanks for the help.