code 335 and 176

Just had a check engine light come on, pulled the codes and got a 335 and a 176, I know 335 is egr related but not sure where to start with the 176. Book says "system lean bank 2" is this a oxgen sensor gone bad or what?
Any help or ideas.....

Thanks

JimmyB
94 SC

"the miles keep going up"
211,750