1998 sonata v6 starting
 

I have recently purchased a 1998 2.5 V6 sonata with only 45,000 miles on the clock. I am very happy with the purchase, exept, it seems to have a fault wereby it wont start occasionally. Its a though the imobiliser is still engaged. I keep activating the lock/unlock on the tab, but that doesn't always help. When it does start, its as though theres nothing wrong.

Could this be a fault with the imobiliser. has anyone had this problem??