My only experience was testing driving the TCH on a hot day with the A/C running (had no idea about the Economy Mode, so assume it was off) . Upon power up, the engine started after about 4 or 5 seconds just sitting there (being a test drive, spent more time than usual just looking around the dash). Out driving around, the gas engine normally was running while cruising with pressure on the gas pedal. Releasing the gas pedal to coast and the engine would stop after 2 or 3 seconds, and remained stopped while at red lights. As soon as gas pedal was pressed when light changed green the engine immediately started. I wish I would have thought to try it with the A/C off, but I ordered one anyway, just now have to wait for it...