1990 Acura Integra My car starts 9 and a half times out of

This car runs great, very reliable:9 out of 10 times itll start great.Like the other day it wouldnt start and i tried it several times,it just clicks.(batterie is great)Then 2hrs later i come back and it fires right up,like nothing was wrong,very iretating.

(I just bought this car a month ago,the guy i got it from says the guy before him installed the key or ignition in a weird way so somebody couldnt just start it easily.)