my 87 F150 With the 300 and the 4 speed
has a weird issue when starting. if the truck
has sat for a while (not overnight, just a few
hours), it will stall immediately after
starting. you have to give it gas immediately
after the engine starts to keep it
running...and if you let off the gas right away
after holding it to keep it running it will idle
really rough And low for a few seconds then
it will pick up and run great. if you try to
start it without giving it any gas it will stall
the first few times and then on about the 3rd
or 4th start it will idle rough and really low
but then straighten out. like I said, this is
only when its sat for a few hours...if you shut
the truck off and start it back up within
30-45 minutes it starts up fine. it kinda
seems like the fuel rail isn't staying
pressurized but I don't know...any help
would be greatly appreciated! thanks in
advance!

 

Could be from injectors that are leaking. Certainly wouldn't be the first time I've heard of old injectors dripping fuel until the rail has fully depressurized.

 

well if that's the issue I'm really ticked off...the truck has 6 new injectors. I pulled the vacuum line off the fuel pressure regulator and it smelled like fuel...does this mean its bad? there wasn't actually any fuel dripping from it but the truck had sat overnight...

what's a good way to test for a leaking injector short of pulling them?

 

I don't think the FPR should be allowing gas fuses into the vacuum hose, so it could be bad. Try unhooking that hose after it has been running, and see if it looks like it's damp/wet. If it is, replace the FPR, they're fairly cheap compared to the cost to repair the damage caused by a leaking FPR (fire, for one)......