Thank you for your reply.
The O2 sensor lean code is indicating oxygen in the exhaust
This code can be set for many reasons...not enough fuel, a vacuum leak, misfire, bad O2 sensor.
What struck me though is the open spout connection.
The spout is a connector that is unplugged to set base ignition timing. This takes the computed timing out of the loop.
Once the timing is set, the connector needs to be plugged back in to allow computed timing.
If the plug is missing or the circuit open it will certainly make the truck run poorly.
This is what the connector looks like.
The spout connector should be over near the ignition module mounted on the inner left rear fender near the hood hinge.
You will need to verify the circuit is intact. Once repaired, you will need to set base timing.
- Place transmission in NEUTRAL (M/T) or PARK (A/T) with A/C and heater in OFF position.
- Connect an inductive timing light.
- Disconnect the single wire in-line Spark Output (SPOUT) connector or remove the shorting bar from the double wire SPOUT connector.
- Start engine and allow to reach operating temperature. With engine at timing rpm, check or adjust initial timing to specification. NOTE: To set timing correctly, a remote starter should not be used. Use the ignition key only to start the vehicle. Disconnecting the start wire at the starter relay will cause Ignition Control Module (ICM) to revert to start mode timing after the vehicle is started. Reconnecting the start wire after the vehicle is running will not correct the timing.
- Reconnect single wire in-line spout connector or reinstall the shorting bar on the double wire spout connector. Check timing advance to verify distributor is advancing beyond the initial setting.
- Remove test instruments.
Check that out and let me know what you find.