I have a 98 F150 4.2 V6 strndrd. I had been having problems with missing for a few months tried many troubleshooting methods. About two weeks ago i thought i would try 1 more thing... On the fuel rail there is an intake valve like that on a tire. I decided to try and clean out my fuel system with a little shot of air after i did this my truck wont get any gas at all. Im not shure exactly what i could of done besides maybe clog up the injectors or the fuel filter or something to that degree. If there is anybody with any insight on this matter I would really appreciate a word of advise.
Battle_Eagle

 

Not trying to put you down or anything, but, why the heck did you do that?

That is the fuel pressure test port so a fuel pressure gauge can be hooked up for testing.
Have you tried to cycle the key on and of a few times (on for 3 sec, off for 3 sec.)? that will prime the fuel system. Do you hear the fuel pump running when you turn the key on? Did you use shop air? You might have blown the pressure hose off the fuel pump in the tank. Change the filter anyway. I don't think that would cause any permanent damage (never tried it), but it wasn't a good thing to do. I would make sure you didn't blow out the regulator also ie: fuel leaking around it or in the vacuum hose. Check those out first.