Chevy classic 1500 with multiple fault codes including p0050,p0131,p0171,p0174,p0300,p0446

I currently am working on my girlfriends fathers truck and it has numerous codes such as;

P0050
P0131
P0171
P0174
P0300
P0446

And I checked the evap solenoid, seemed to have high resistance in the solenoid but was getting good power and ground to the circuit. The codes also pertained to bank 1 and 2 sensor 1 faults and a random misfire and both banks have a lean condition. Please help, I would like to resolve this problem soon, it also stumbles and seems to want to stall when going up large elevations.

I currently am working on my girlfriends fathers truck and it has numerous codes such as;

P0050
P0131
P0171
P0174
P0300
P0446

And I checked the evap solenoid, seemed to have high resistance in the solenoid but was getting good power and ground to the circuit. The codes also pertained to bank 1 and 2 sensor 1 faults and a random misfire and both banks have a lean condition. Please help, I would like to resolve this problem soon, it also stumbles and seems to want to stall when going up large elevations.

Hi and welcome to AF. Need to post this in the proper forum (C/K, '99 & newer Silvy, etc.), and we need to know what year, engine, mileage, etc.

The truck is a 2007 chevy 4.3L 2wd single cab auto trans.