I didn't tell the whole story, I will be supplementing the missing fuel from another fuel source. A closed loop air-fuel ratio will be maintained. The on board vehicle computer will think it is supplying all the fuel. Thanks Jon In a message dated 5/19/99 12:51:46 AM US Mountain Standard Time, lester@cambs.net writes: << Surely less fuel, same volume of air = weak mixture = pinking = holed pistons? But form my experience, if you do the opposite to a diesel, you get load more power and it works with petrol engines but not as dramatically. >>