95 F-150 starting problem

I have a 95 F-150 5.0L with dual tanks that occasionally will not start. The motor cranks, but no start. After stomping around for a while and cussing, it will decide to start. Twice within the last week it has shut off while driving. Once again, it will not start until it decides to do so. This happens with both a hot or cold engine, and it is getting worse. Used to happen every few weeks, now it happens once or twice a day. I've posted a thread on this before and checked out several of the suggestions. I've changed the fuel filter and checked out the tank selector switch and inertia switch. Even when it does not start I can hear the fuel pumps run for a second when I turn on the key, so I think that's telling me I don't have a wiring disconect to the pumps. I'm assuming it's a fuel problem, but could be something else. Any thoughts are appreciated.

Do you have spark when it doesn't want to fire? Could be the ingition control module.

Thanks. I'll check. Have been so focused on thinking it's a fuel problem that I've not checked for a spark.