2000 lincoln town car intermittent starting, sometimes will crank but not start then will subsequently start and run fine. Does not happen all the time. May be fine without a problem for a while and then not start. Always cranks (starter turns engine over)fine but does not run. I may have to turn the key to run the starter several times, nut eventually it has always started/ran ine after several tries on the starter. Does not seem to be any identifiable commom comditions as to when this problem occurs.