Ignition timing?

Run the vehicle a few miles until it is at proper operating temperature.

Then pop the hood and attach timing light. Next climb under the vehicle and mark 10 degrees before top dead center with a piece of chalk for visibility.

Next pull the spout connector out right by the distributor, after that is done, loosen the distributor enough to turn it by hand but not the idling engine vibrations to change.

Then start vehicle and alight the 10degree line to the marker on the vehicle, torque down the distributor and shut off vehicle.

Remove the timing light, and put back in the spout connector and your good to go.

The only thing you can set is base ignition timing. The ECM takes care of timing on a moment by moment basis after the engine is running.

In order to set base timing you need to disconnect the spout connector, start the truck and set timing to about 10 deg BTC. Some people set it as high as 13 deg, but then you run the risk of detonation at that setting, plus emissions tends to go up the more you advance the timing.
Shut the truck off, reconnect the spout connector and that should do it for ignition timing.

The spount connector is a little plastic doohicky on the wire bundle coming off the TFI module. I just pull it out and set it somewhere safe while setting the timing.

I do not know what the rest of the story is, but for the symptom you described, look at the fresh air tube between the air cleaner and the throttle body. If any air sneaks in through a leak, it wont get measured by the sensor and no fuel will be added to the fuel metering calculations.

This is a vacuum leak guide that will help with this.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please let us know if you have other questions. Thanks

It's usually right near the base of the distributor, or I'm thinking also could be near base of tfi depending on model, hangs off the wire harness, small plastic part(2 pieces) at the end of a couple of wires. From the factory usually the end plug(which you will pull out) is wrapped with friction or some sort of black tape. When you disconnect it, engine will revert to base timing