I'm getting a P0175 code on my '97 Suburban, it says that BAnk 2 is too rich, I like to know what causes the engine to be too rich, please help

Use a VOM on o2 sensor black lead.

.6 volts is dang rich .3 volts is dang lean.

http://www.kemparts.com/TechTalk/tt07.asp

http://www.obdii.com/articles/Replacing_Oxygen_Sensors_Preventive_Maintenance.ht ml

Later,

I'm getting a P0175 code on my '97 Suburban, it says that BAnk 2 is too rich, I like to know what causes the engine to be too rich, please help

Raw unburned fuel causes a rich condition. Could come from a leaking injector,regulator, misfiring plug or any thing that could cause an excess of fuel into the exhaust.
Rarely will a O2 sensor cause this problem.