Could be. First thing in order would be to check all your connections to the starter, battery cables etc. Is it random, time dependent, or temp dependent?
BTW: My car refuses to start when it's been sitting in the cold. No click, nothing. On the second or third try it'll fire right up. So far, it's been tough to duplicate what my wife has told me, so I'll wait. Did the same thing last winter, I tuned it up and replaced teh OVP. By the time all was said and done it was spring so the hard start issue disappeared - until now.