P0171/P0174 codes...not the MAF :(

I'm back from Moab and finally got to swap out the MAF that was a main suspect in my lean banks 1 and 2 codes (171/174 codes), but the CEL came back on after about two hours of driving around town doing errands.

I can't find any leaks in the intake from the airbox to the engine. What else should I look at?

Also, I figure regardless it's time to clean or change the EGR valve, and I see there are some on ebay for under $50. Easy enough swap, but my question is should I clean the EGR tube too, and if so, how?

I watched a video on here from years ago, and while it's not complicated, it is time consuming. There was also a tool mentioned that made it much easier, but the link is broken now.

Is there a quick way to at least partially clean that tube? At 175,000 miles I'm guessing it's pretty bad.

Suggestions on either thing appreciated...the CEL is bugging me, and no, I'm not going to put black tape over the light :P

This may help https://www.youtube.com/watch?v=4mZjSiIbmFQ

He has another vid on tube cleaning

I cleaned the EGR valve and replaced the gasket. Cleaned the tube as best I could from that end with a wire and some injectable sea foam. Actually worked really well...idling very smoothly now.

Codes are cleared. We'll see if they come back.

I just bought the tool to do mine. I'd let you borrow it, but they are so cheap you might as well buy one. Getting ready to clean out my tube and do a bunch of other little repairs. Best of luck with your codes. BTW, are there any symptoms besides the codes popping up? loss of performance or anything weird?

Here's a link to the tool:
http://www.amazon.com/Herco-HE78-Tro...dp/B000EELFOM/

I actually solved the problem I think. No, I didn't have any change in performance I could tell, just the codes.

When I cleaned the EGR valve, I noticed that the bolt further in towards the engine centerline was barely hand tight, and the gasket was a bit ragged and had some carbon right at the edge near the loose bolt. With the new gasket and properly tightening down both bolts, I think I sealed my leak path.

It's been running great with no CEL since :)

However...that tool really is too cheap not to have...