***HELP***Possible Air Leak Issues

OK,

My MAF reading is half of what it should be. I have changed MAF's and made all of the needed adjustments. C&L is telling me that there might be an internal air leak in the intake. The reason that they believe that there is indeed a leak is because, when I activate the EGR with a vacuum there is absolutely no affect on the motor. I purchased the car with the Explorer intake already installed. Any one have any similar experiences or ideas?
 
You don't know what was done or not done (blocked, etc) to the EGR plumbing. Put a vacuum gauge on the manifold and note the reading. It should be near 20" hg.

For a MAF to read half of what it should read is a TON. I'd double check the MAF itself, and it's wiring.
 
Okay I figured out the EGR issue. I think I have a later model Explorer intake that does not have the EGR tube in the middle. That explains why the EGR does nothing. Would open breather caps on the valve covers cause an issue? I am going to cap one and then run the other back into the throttle body tomorrow. Hopefully that will have an affect. Also my PVC valve grommet is way loose. I am also going to change that. What do all of you EXPERTS think.