hard start

[73stallion]

i've still got an issue with my '99 sport 4.0 OVH hard starting. i've installed new double platinum plugs, new air filter, new fuel pressure regulator, new fuel filter, it's still having a hard time kicking over. i have no check engine light on. sometimes it'll start on the second try, sometimes it won't start until the 4th or 5th try, and i'll usually give it a little throttle when that happens and it helps. it's primarily when it sits for about 10 minutes or so. if it sits for an hour or so it'll start a lot easier.

any ideas at all?

 

[Redneck0907]

intake seals? thats what id suggest.. do a seach see what ya find.. i got a 5.0 so i dont have issues with that, but i think i hear its commom on 4.0's..

they should be like o'rings pull the intake manifold off the block.. and they seal the intake manifold to heads if im correct.

 

[Lizard]

Ok, this thread is a little old, but on my 1999 5.0L it was the crappy pinch clamps (CV style) used on the rubber hoses connected to the fuel pump in the tank, that was causing this problem. Check your fuel pressure "leak-down" time. Mine went from 65psi to 0 in a matter of seconds after turning off engine. Makes it hard to restart after sitting for 15+ minutes. Many people think this is a "check-valve" problem on the pump causing this. I wonder how many pumps have been swapped out when it was most likely those sh!tty pinch clamps causing a leak? Only pain was dropping the fuel tank in order to get the pump assembly out. Get some good fuel injection band clamps and replace those pinch clamps. Also inspect those small pump hoses for cracks and replace as necessary only with submersible 35R10 grade fuel line designed to be used in fuel tank. Do the fuel pressure leak down test before replacing intake gaskets and other crap...