1987 Bronco 5.0 automatic
 

Hey guys, the bronco wont start first time, it takes 2-3 tries.
Also, a stumble while accelerating, not sure if they are related.
Hooked up vacuum gauge, dead steady.

Replace the fuel filter, if thats doesn't do it replace the pump. Just for fun: Turn the key to the ON position, then wait some seconds, then turn it back, do this 3 times then try to start the truck. If it starts easier then you will be 100% sure it's fuel-delivery related.