2000 Mountaineer Rough Idle, 4.0 SOCH motor.

[Jraymer360]

Okay so it runs fine when warm but idles rough and dies when cold. i got it to idle decently, but still rough. You can hear an obvious vacuum leak.

i've researched this problem and i've come up with this : the intake manifold "O-rings" need to be replaced. is this the same thing as the upper and lower intake gasket, just they're really just O-Rings?

this is the gasket i found on Oreilly Auto's webpage :

Those are what they are talking about right? that's the only trouble i'm coming up with so thanks guys for your help.

 

[Earl43P]

Those are them.

You typically get a CEL with lean bank codes (P0171, P0174) if it's those seals.
Common problem.

My recommendation is to remove the hood and sit up there to get this job done. Hard to see all the bolts otherwise. Might want to replace the thermostat while you are at it.

 

[Jraymer360]

Those are them.

You typically get a CEL with lean bank codes (P0171, P0174) if it's those seals.
Common problem.

My recommendation is to remove the hood and sit up there to get this job done. Hard to see all the bolts otherwise. Might want to replace the thermostat while you are at it.

i think the bulb is burnt out, i still have to check for codes as i just got a scanner. and thanks for the recommendation, my uncle ( the owner) just replaced the thermostat about a week ago, right when the problems started arising...or so i've been told.