05 Tib GS not always starting, just cranks

My 05 Tib GS 2.0 4 cyl starts great most of the time....
Once in a while it will just crank and crank, but not start. I'll remove the key wait a min and bam, starts right up.
Replaced the crankshaft sensor, didnt fix.

any other ideas?

Thanks all!
Jon