Warm. When the engine is cold it's not reading the O2 sensors and it's running off the fuel and timing tables that are stored for cold idle. Adjust it when it's warm and the EEC will transpose the new correction factors into the cold idle tables to update the tables. Good luck.
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more!