[laserfan]

I absolutely cannot imagine an electrical accessory drawing enough current to impact the engine operation, unless of course something is amiss. The alternator, like the a/c compressor when running, by virtue of the belt(s) puts a drag on the engine and THAT affects the engine performance and MPG, just like wind or tire pressure or bed loading or anything else that drags on the engine.

But DRL affecting spark? I don't think so, at least not (even) to the tune of 1/10 mpg.

But I'm willing to buy the argument if the alt. has a clutch or magnetic brake or something.

Hey Whaleya, do you recognize this? "B as in B, and S as in S!!!!" (from an ex-fellow MNesotan)