2004 Ford Explorer wont start

I have a 2004 Ford Explorer with 160K miles V8. This car sat for about a
year and a half. My son got his license, charged the battery, aired up the
tires and it started. Sound a bit rough but later found out the exhaust was
disconnected. After driving it for 2 weeks the fuel pump went out. Towed it to
a garage put on a new fuel pump and it would crank but not start. We then
replaced all 8 coils and spark plugs and same thing. The mechanic said
there was oil and gas on the passenger side plug when he went to change
them. This is a sign of a blown head gasket however all other signs that
would show this were none existant. He is at a loss at what is going on. He
checked the fuel pressure and it was a little low but still in the normal range.
Anyone have any idea of what could be going on.