My 1995 ford f-150 truck stalled the other day and wouldnt start. After letting it sit for 5 minutes, it started and I drove it 500 ft. Then it stalled again and wouldnt start so I had it towed. About 3 hours later I tried starting it again, and it started but only ran for 10 seconds before it stalled and wouldnt start again. I tried again after about 5 hours, and it starts and runs fine now. Why is it so unpredictable, and what is wrong with it?

You need to have the factory security system scanned, it is most likely locking you out due to a fault.

2004 Ford 150 5 4L Stall No Start P0191 Fuel Rail Psi Sensor P1233 Fuel...

On one of the occasions when it won't start back up, someone will need to figure out if you have lost spark to the plugs or fuel to the injectors to be able to troubleshoot the problem.

Fuel injectors may be dirty.. or plugged. The car just sitting there may have caused the gas to go bad which may have given them a head start on plugging from the get go. Get some cleaner for it.
When the dash lights blink, is it unlike anything you've seen it do before?
check the detail :

http://www.xcardiag.com/search/?q=engine

did u change the gas filter if not i would try that good luck gordon

sounds like the distributor needs replaced

Depending on the miles the transmission fluid most likely needs flushed and changed.

theres a relay under dash on drivers side that causes that when relay gets hot it wont start but it cools off it will start and it will do it worse in the summer

Check to see if the fuel pump is running after it shuts down...could be a relay or the pump itself (overheating internally) Checked the fuel filter yet? Some crank sensors need to be shimmed. If it's too close to the flywheel even though you recently changed it, if it's too close to the wheel it can fail again. May not be the case but worth checking over. Also check the ceramic resistor on the left fender near the master cylinder if you have one. That too can cause problems.

there is a recall on the cam sensor that is causing these to stall. i had the same problem and after letting it go for two weeks it finally wouldn't start and i burned up the starter, so i recommend taking it in as soon as possible. all work should be free at any ford dealership, just be cautious because they always wanna do more than they have to.