ok so i got a 1990 4.0 and i put a new exhaust/intake gasket on it and ever since then my jeep wont start everyonce in a while and what i found out to get the jeep to start is i just pull the fuel line off the intake and put it right back on and that solves the problem. its like it floods the fuel rail everynow and then. anyone know what could be wrong

 

If you hold the pedal on the floor it will cut off the fuel while you are cranking. You might do that to help see if it's flooding. Any black smoke?

You sure you didn't brake the map tube while you where working on the manifolds? Those things are flimzy, and cracked or plugged it will make it run supper rich.

 

Bad fuel pressure regulator? Doesn't it keep the fuel rail pressure at the proper level? Did the vacuum line slip off it?

 

No smoke at all and what is the map tube ??

 

On your 90, the map sensor is up on the firewall. Just that it's supper easy to check. It has a little tube routed down around to the rubber plug on the inside of the throttle body. If it's off, cracked or plugged, and the sensor doesn't get good vacuum it will dump in more gas thinking you have your foot in it. Mine got brittle and broke more than once. It's easy to brake it messing with the manifolds.

When you say you are pulling the fuel line off the intake, do you mean you are pulling the vacuum line off the regulator on the fuel Rail?