first time here,, i got a 99 4x4 with a 5.4, k & n intake and 78000 miles its having problems starting sometimes,,it did this even before i put the intake on, i changed the fuel filter that needed to be changed "very plugged up".. it will run fine once i get it started with some starting fluid but it just seems like it isnt getting any fuel "sometimes" on startup...any suggestions thanx in advance

 

How bout check your fuel injectors? Considering it's sometimes at starting, you might not notice the engine missing at speed, but a clogged injector could be why it won't easily start sometimes. Get em cleaned or replaced and try it out.

 

are injectors expensive??

 

Don't quote me on these prices, it's been awhile. You can get your injectors cleaned for under $100, or get new ones for around $400. I'll say try cleaning them first, won't hurt too much, they should last awhile, they could just be dirty.

 

try running seafoam in ur gas tank and threw ur vac lines.... search or read the can. its no miracle in a bottle but hey the 5 bux to try it is worth the moeny if u might end up buying parts that are alot more.

 

thanx will try,, do you think theres any chance its a fuel pump or some sorta relay

 

back again,, i tried the seafoam cleaner and the truck still seems to sporadically not want to start,,i put a snap-on solus computer on it to see if anything showed up and nothing no codes, i checked the pressure on the fuel rail and theres 30-45 psi when running and 35-45 when off,,, i did however notice the pressure bleeding off kinda quick down to 20 psi in like 15 minutes,, i switched the key to the on position and the pressure came immediately back up,,any more suggestions?? thanx in advance.....

 

I'm not an expert on the electrical components of an F-150, but it sounds like a throttle position sensor. The engine will not crank without the gas petal being in the idle position. You can force it to start by putting gas in the intake or using starting fluid. The next time it won't start, press and release the gas a few times, or just pull the throttle body closed with your hand and see if it starts. It may be gummed up with dirt or the throttle cable might be binding, or that plastic guide may have broken off the throttle cable and isn't letting the intake close completely or something. Just an idea, but Johngs or JMC, or some other expert may come along and help you.