My wife's 95 12v is leaking diesel. If the truck is parked nose down on say a hill it'll start the next day but if the nose is uphill it'll take like 5 minutes to get it started. Even then it stumbles and bucks for a good minute or two. My guess is that the fuel is draining back to the tank. The truck will fire right up at first but once it burns the fuel in the injector pump/lines it dies and then takes forever to start. I didn't see any fuel lines that were wet and the fuel filter is not leaking. Although I can not see behind the fuel filter without taking it off but the lift pump is soaked and the fuel is running down there on the engine block. The thing is the whole lift pump is soaked. Not just out some gaskets or something on the lower part of the pump. So I'm wondering if something is leaking down ontop of it. (Wishful thinking?) But the fuel filter is in the way. Before I go replacing the fuel filter just to look behind it... is there anything there? Perhaps a line running out of the top of the lift pump that might be heat rotted? If it is the lift pump... What all is evolved is replacing it? Just taking off the starter to get to it I'm guessing?

Oh yeah, Once the truck starts it runs perfectly fine. And even if I park the truck on a hill nose up it'll start and run fine as long as it doesn't sit longer than a few hours. It's not a pouring leak... just a small annoying one that lets air in the lines somewhere.

 

If you look just in front of the fuel filter (top) hugging the engine you will see a rubber line. This line runs from that point to a metal line over the top of the trans and is a popular line to crack and start leaking and letting air enter the system. May be time to replace it.

 

I agree with J-body, this would be the first thing to check.

 

yep sounds like its that rubber fuel line