Copied from another post:
the idea of the heat cycle method is to run the truck 5 times for 3 minutes each time (while making sure the engine reaches 200F). This is the first step. Once your done that, the second step is to run the truck 3 more times for 5 minutes each run. Once again, getting the engine up to temp. If the engine goes above 200F during the 5min runs, thats fine, just as long as it doesnt go past 250.
This whole time, u should run the engine as rich as possible, just as long as the truck keeps running and you can get it to 200F. If it is too rich at stock settings, you can lean it out a bit. I had to lean my F4.6 about 1/2 on both