2005 Avalanche which I bought new in 2005.

Not sure they are related, but my fuel gauge isn't working right. Shows empty most of the time, but occasionally goes to full. AND, it just just showed P0101 Trouble Code - Mass Air Flow (MAF).

Thoughts on what is going on? I'm assuming fuel gauge sending unit in pump is all but dead?
MAF dirty or defective? I have never cleaned it in the 15 years I have owned the truck.

Any thoughts and advice would be appreciated.

 

I think you are spot on. Use only MAF cleaner to clean it.

 

Yep, fuel pump/sender are giving you fits. The MAF cleaner and MAP cleaner can be had at the parts store and follow directions. At 15 years old, IMO, I would replace both and clean the throttle body.