Hard start when warm/hot

[msaudinaitis]

2000 expedition EB, 4.6 triton, 69,000 miles. In the last week has become difficult to start when engine is warm or hot. Now it cranks for a while when cold too. Owned since new and always started on 1st crank. 1st crank doesnt do it anymore. Battery is strong and charging system good. Runs normally when finally starts. No fault lights whatsoever. Is there a fuel system check valve that could be bleeding down? Also thinking fuek pump but it runs normally once started. Dont want to pull the tank if there's other areas yet to look at. Thanks for your time.
I read in some post to turn the key to 'on' for about 5-10 seconds twice, then try to start it. That works and it's starting much quicker (not cranking for 10-20 seconds before starting). SO I'm definitely leaning toward something with the check valve. Any quick fix if it is, or does tha tank come down?

[copcarchris]

Check fuel pressure after keying it up. Should be at least 45 lbs. If not, check for plugged fuel filter. If OK, drop tank.