While all do worse in the cold, I think there are common factors and some specific to each type.

For years, I thought the 'rule of thumb' for when to shut down your idling engine was if you would be there more than 5 minutes. A guy on TV a day or two ago, said shut it down if you'll be idling more than 10 seconds! I'm concerned that I'm going to wear out my starter on my conventional Explorer if I do that at each of the 15-20 lights on my 'surface route' to work, that I don't hit on green.

I have a ScanGaugeII ordered and am waiting for it to arrive now. I'm just hoping with the instant feedback that I can make some improvements in its mileage.

Benton 24may08

 

Hybrids have a big advantage here because they don't use a conventional starter. They "instant start" with their hybrid motors. Because of this I shut down my hybrid much more often than my non-hybrid. I'll only kill the engine in the non-hybrid if it can be off for at least a minute or so.

 

Yeah I have a ScanGauge on my diesel smart. It's great! Winter fuel economy goes down by maybe 5-10% where I live.