i'll replace that one and get back with you all. After I wait a couple of days and see how it runs. I don't care for any more false celebrations on my part.

 

Mine was like that. I think it was bad shape on the inside. It was losing vacuum through the wall of the tube
.

 

A bad PCV valve can make your engine do some bad stuff too. That is cheap to replace too.

 

New hose on. Now wait for the overnight cold soak. Pcv? The rest of my hoses are good to go.

 

Not to thread jack but my trucks having some similar symptoms. I wanna do the carb cleaner test on my vacuum lines, which hose are you guys spraying into the brake booster?

Also I wanna change my PVC valve, I know how to pop it out of the valve cover, but how do I take off the little water jacket that's wrapped around it? I'm stumped

 

My truck is new to me just like the OP. But a friend who's had his 98 Expedition for years and years told me that a lumpy cold start might signal when it's time to change plugs.
Before I would start that though, given the mileage and what he's already done, I might try pulling the idle air control valve and run some brake cleaner though it.

 

The PCV is located on the passanger side valve cover right on top. One tube connected to it. I don't know of any jackets on them. But a failed or faulty one can cause vacuum leak, rough idle, oil burning, misfire, I am sure there is a longer list of things that they affect. They are less than 5 bucks at the normal parts places. I would consider replacing the rubber grommet that it fits iñ to if you can get one.
While you are on that side that gives you a good view of the tubes that connect to the intake. Cleaning the idle air control valve is a good idea also. If you have the carb cleaner in your hands its 1 plug and 2 bolts. Quick and easy to do. If there is junk in there Signal 2 is right, it will idle like crap.
We are not spraying into any tubes. Just around where they are connected. While the engine is running spray the ends/connections. The connections on the back of the intake have a history of leaking over time and age. They are not hard to get to if they need replaced. The cleaner will change the idle of the engine and you will have found the leak.

 

ICV is about $55 bucks. I've replaced it, Air temp sensor, intake and injector clean, pulled throttle body and cleaned (filthy), cleaned mass air flow sensor. Ill get PVC tomorrow and replace w/ grommet if I can get. I think it could be plugs. If I let it idle like crap and don't put my foot in it to warm up it throws INTERMITTENT MISS FIRE code. Kinda nervous about changing plugs from all the horror stories I've heard about plugs snapping off. Go slow half turns in and out, should be okay.

 

I want to replace my coil ons also. I dont want to pay $58 a piece for motocraft. Was thinking about accel super coils. What plugs will be compatible with that set up?

 

Decided I should look at my pvc valve. I have heard a hum coming from passenger side of my engine for about six months, felt pvc valve and it was buzzing like a mother. $5 give or take a penny or two, no more humming. I will repost tomorrow if no codes throw and start up is good.