So i was having the issue of codes running lean bank 1 and 2. also the evil random missfire. I replaced the 2 O2 sensors, and all codes cleared. Now im getting low voltage bank 1 and 2. any ideas? truck seems to be runnning great, only issue is at start it cranks more than normal to start.

 

what vehicle and sounds more like a fuel delivery or vacuum issue

 

2000 Silverado 4.8

I agree that the start up issue leans towards fuel. But don't understand why the codes would show after the new o2 sensors.

 

many many things can cause 02 sensor codes, usually unless its an 02 heater circuit code I fix everything else first then go after the 02 codes. Most times they are set as a result of something else being bad