Won't Start!!!

[mustang93]

Hello,

I have a 1993 mustang convertible that I have just changed from a 4 cylinder to a V-8. The problem that I am having is that once I crank the car and let is run for a while and than cut the car off it won't start back up until you let it set for a while. if you put the car in second gear and push it off it will start(?????) I have check the coil, distributor, wiring harnesses, computer and fuel pumps. I'm hoping someone else has run across this problem and might have an answer

Thanks in advance