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[bismic]

It sure COULD be fuel related. you stated that you checked it pretty thoroughly though. Just an FYI, it is wise to use Motorcraft, Racor, or International fuel filters. Some aftermarkets do not perform as well. Sometimes, folks have not lubed the o-ring on the HFCM (frame rail filter and fuel pump) or they have not properly screwed the cap on. Air gets in and it is hard to start. Sometimes the caps crack and it goes un-noticed.

Are you cycling the key on and off after changing/removing the filters. this is important to getting the air out. There is a specific procedure that I can post if you need me to.

Most folks say you can check fuel flow by opening the secondary fuel filter, removing the fuel, and then cycling the key (do not start), to check for fuel flow filling the secondary filter housing.

Also, you can drain water from the plug on the HFCM (6 mm allen wrench). I always drain it into a jar to get a good visual on the quality (dirty, water, etc).

You may know all this, I just couldn't tell from your post. Actually the best thing to troubleshoot your fuel system is a fuel pressure gauge. I will have one by year end (saving the $$'s).