Working on my friend's Sierra that still has these three codes. So far I've replaced both downstream 02 sensors, PCV valve, air filter, rear shocks, oil and filter, plugs and plug wires. The P216E is a new code since I started working on the truck. Rented a fuel pressure gauge but haven't found a schrader valve yet. Tomorrow I'll get and install the two upstream O2 sensors and the MAP sensor. I sprayed CRC sensor cleaner to clean the original MAP sensor but don't know if it's related to these codes or not. Any ideas?
