Trouble Code Shuffle----egr related

[simpler=better]

Just a shot in the dark, but check the hoses on the back of the egr solenoid (black 6 splined dealio right behind your coil pack, seen in both photos)

 

[StWeiler]

Update:
Finally got irritated enough to take it to the dealership and have them take a peek at it. By their testing the P0402 was due to a faulty egr valve solenoid (was not closing completely). They determined the P0174 was due to the MAF (which I have not replaced just yet).
They also highly recommended the new and improved updated computer programming to the tune of $90....which I allowed them to do.

 

[RonD]

You clean MAFs first, replace only as last resort

http://www.therangerstation.com/tech_library/CleanMAF.html

 

[StWeiler]

I"ve cleaned it 10x's in the last 2 weeks, we are at the last resort