Giles: Slightly off topic, but here goes: EPA regulates 3 pollutants for gasoline engines: unburned hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). Oxygenates are compounds such as alcohols and ethers (remember MTBE?) that contain an OH group. Ethanol, for example is C2H5OH chemically. Under ideal conditions, all hydrocarbons will combust to make CO2 and water (H2O) using the equation: C7H16 + 11O2 -> 7CO2 + 8H2O. When an engine is cold the reaction often doesn't go all the way to CO2 but stops at CO (a regulated pollutant). Oxygenates in the fuel "partially oxidize" the fuel molecule by adding the OH and are said to chemically lean because they require less oxygen for complete combustion. They help the reaction go to CO2, thus lowering CO emissions. Racers who use ethanol have to increase the size of their jets to accommodate the "leaner" fuel. Pertaining to this thread, the boiling point of ethanol will have no effect on Marc's problem and I agree with Larry on most points regarding vapor lock. However, because of its volatility characteristics, ethanol depresses part of the distillation curve and THAT could lead to driveability problems under certain conditions. Hope that helps - sorry for the nerdiness
