Car is parked with the nose elevated slightly, and it refuses to start, though it turns over. No detonation in the cylinders either.

Car is parked nose level or nose down, and it starts right up with absolutely no problem.

I just bought a new fuel filter (not fram) to install soon, but does anyone have any other ideas until I get it changed?

 

Fill up the tank.

 

You're funny. It even did this at the gas station after filling it, and I don't run below 3/8 tank.

 

check the oil lately?

 

Constantly.

 

Maybe your fuel pump. Downhill its got enough pressure and vice versa.

 

How long has the gas been sitting in the tank?

 

Since I last put it in a couple of weeks ago.