I just checked my new to me Blazer with my OBD Tester. It showed two codes: PO172 - System to Rich BANK 1, and PO175 - System to Rich BANK 2. What does this mean? I checked the tech. articles for these codes, but they are absent from the list. Any help?

 

I just took off my MAF sensor and cleaned it. Wasn't to dirty. But the bottom of the air filter box had a pile of dirt/sand in it. So I took it off to bang it out. I noticed that the "air intake snout" attached to it was very small. The opening could not have been more then 2 1/2 inches big!! I then looked inside the engine bay to see where it connects to get the outside air. The hole in the front grille was more then half way blocked by the headlight! This motor really must have to suck hard to get enough air. So I disconnected the "snout" and placed the air box back in clean and with a nice 3 1/2 inch open hole. And has enough room between it and the grille to allow more air flow.