Hi, I am John Mc, a Ford dealer tech. I hope I can help you quickly and accurately. One moment while I work on your problem.
From your description it sounds like you either have a bad mass airflow sensor or a dirty one. I would suggest removing it and cleaning it with some electrical cleaner or brake cleaner. After this take the battery loose for 5 minutes and see if it is better. If so you just have a mass airflow sensor problem. If not follow the pcv tube from the back of the drivers valve cover around and to the intake. Check any of the rubber tube parts for rotting. They are bad about rotting out and causeing a vacuum leak, this will cause the engine to run rich with it trying to compensate. One of these two issues should be your problem. If not it is a bit more complicated and you should have someone check it.
Anything further and you will need some equipment to properly check out the systems.
Is the mass airlfow sensor on top right by the air cleaner canister
I will go out and check these things.
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The truck got hit pretty hard and we even had to change the valve cover on the passenger side because it had a hole in the back. The wreck may have pinched some hoses on the back side of the driver side of the valve cover area.
This is a pretty large hose so it is either pinched or has come loose.
Is the hose coming out of the valve cover(driver side)?
Yes should be one on the back of the drivers side valve cover.
Will be back. My guess is that the collision hurt it.
The two big hoses look good coming out of the back of the valve cover all the way around.
What is that thing under the alternator that a small vacuum line plugs into?
Sorry, I was not notified of your reply.
That is the coolant control valve. This should not be a big enough leak to cause your problem. It is possible if they replaced the plastic manifold that they did not replace the gaskets. Some people try to reuse them. If this is the case it could be your vacuum leak causing all the problems. To be sure if this is a vacuum leak you need to get a scan tool and read the long fuel trims and short fuel trims. Add the long and short for bank one and then for bank 2. Each should have a total of under 10%. If not you definately have a vacuum leak. At this point you would either have a bad pcv valve itself or bad intake gaskets.
When I unplug the mass airflow sensor the RPMs do not fluctuate. When I plug it in, the RPM's go up and down.
Does this mean the mass airflow sensor is the problem?
This is very possible. As I said earlier this is a common issue with these trucks. First try cleaning and taking the battery loose for 5 minutes. If that doesn't do it then try replacing the sensor and leave the battery loose for 5 minutes.