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