I took my 7.3 Ford van to Bill at Powerstroke specialties in Buford, Ga 2 weeksago and had him re-flash the ecm.He explained to me that The 7.3 FOrd vans were shipped to be in compliance with the California emissions, and they were cut way back to meet them, not running the way they were built to run.More power? It is like A jet engine now, a rocketship.Burn rubber? no problem..lol.I have found I now do not have to give it as much gas to go through the mountains to maintain speed.So much more enjoyable to drive.Fuel mileage? I gained 1.5 to 2.0 mpg more immediately, and that was running it hard.I know I can get more out of it by changing to the optional 3:55 gears form my 4:09 I have in it now, and add cruise control also.The downside? When I get into it, Alot of black smoke out of the tailpipe.I jinda felt sorry for that motorcycle guy I passed the other day in Georgia, on the 2-lane..but he was going 31 mph in a 60...