Hello. My name is XXXXX XXXXX I will be glad to assist.
These two codes indicate a lean condition. This is usually caused by a vacuum leak. Inspect all vacuum lines and PCV valve. Listen for vacuum leak.
That is very possible. With the engine running, listen for a hissing noise. You can also use starting fluid or brake cleaner to spray in areas of the engine, If there is a vacuum leak, the engine will suck up the starting fluid and change RPM or stall.
Most vacuum hoses are black plastic or rubber.
There is vacuum supply to the heater control but if vacuum supply to the heater control was missing, you will only have defrost mode. Check the small vacuum line, under the hood, that goes through the fire wall, by the heater box on the passanger side of the truck. Under the glove box is a connection. Make sure you have supply vacuum there.
On the upper intake manifold, drivers side, againt the fire wall is a "T" fitting with lots of vacuum lines connecting there. Inspect for broken/damaged lines.
Your welcome. Please let me know I your have any other question. I would also like to know your results of testing and what you found with your vacuum line inspection.
Thanks for the accept again.