Fire but wont start

I have a 1986 vette that has been sitting in a garage for several years----it was started periodically ---when I decided to get it re registered and back on the road I found the battery was dead and replaced it ---the engine turns over fine but it will not fire up and run now----i tried spraying a little starting fluid in the intake and it would try to fire but wont start---the gas in the fuel tank is a mixture of old and new gas mostly new and fuel restorer additive --it did run on the old fuel a couple months prior---what could the problem be is the fuel pump located in the gas tank and what is the location of the fuel filter. Also can the can I check the engine codes by jumping across the connector and reading the engine light blinking or is it required to buy the analyzer for this. Help my girl friend is going to love me ----thanks jziggyp