car starts only when it feels like it, should I shoot it?

What is your question?

car starts fine for a week or more and for some reason wont start The motor cranks but wont start and then it starts after sitting for a while. then runs for a while until it does it again. I have replaced battery and tuned it but still have this start no start problem, I have noticed the key seems to be giving me a problem by not engaging the starter until i keep turning it for three or four times but that just started happening. The car starts within a second when it feels like working it is a 91 corvette vin 8 convertible

What makes this problem better or worse?

nothing

How long has your 1991 Chevrolet Corvette had this problem?

about two years