My 2002 E150 5.4L intermittently will crank but not start. If I let it sit for a while it will then start. There are a lot of people having this issue all over the internet but no one seems to have solved it. My mechanic thought it was due to my alarm system (after market) so he removed that but here I am again with the same problem. Anyone have any ideas? Seems to be a Ford issue.

 

You need spark, fuel, compression and air for the engine to run. I would start by checking for proper fuel pressure and spark when the engine refuses to start.That problem is quite common on other vehicles too.