Try this:
Make sure the fuel level is between 1/4 and 3/4 and the engine is cold.
Start engine, idle cold for approx. 2 min, 10 secs.
Accelerate to 20-30 MPH, Maintain steady speed for approx 3 min, 15 secs.
Accelerate to 40-60 MPH, Maintain steady speed for approx 15 mins.
Decelerate and come to a stop. Idle in gear for approx 5 mins.
WARNING!
It is absolutely essential to keep the RPM's below 3,000 and the MPH below 60 for the duration of this test!
This won't be easy to do, unless you have access to a dyno or a race track, since traffic conditions could ruin the whole procedure and you have to start again with a cold engine.
Zee