a wet shop rag and an air gun. and it would depend on the pressure the pump was putting out on how well it was running. it kinda contridicts what ive already said but it may behoove you to take a look at your fuel pre heater as they are prone to air leaks.

 

Okay we'll I will be messing with it all day tomrrow and I will let y'all know what I figure out thanks for the help

 

Mine has a return line leak ... stumbles @start up ... then fine ...

If it were pre-IP it would do this .... most likley, its gonna be line from tank to Lift pump .... or @ fuel filter .. my F250 drove me nuts with this kinda stuff ...