[QUOTE="Remco"] One would imagine that all these errors accumulate (expansion, fuel indicator) so maybe with all errors added in you'll see that 30-50 miles discrepancy.[/QUOTE] I agree, so far. [QUOTE] The only way to know for sure is to gather imperical, recording mileage and gallons because you don't know if you can trust your gauge. It would at least eliminate it as a variable and possibly[/QUOTE] accuse it. I think we're having a miscommunication. What I'm challenging here is whether the gage reads more proportionally to the actual weight of fuel in the tank in the winter rather than summer. E.g. in winter, I get about 220 miles by the time the gage indicates half-full. In summer, by contrast, I get about 270 miles. Roughly. [QUOTE] Non-uniformity of the tank just tends to make the error worse as they don't linearize the indicator very well. Of course, the tank shape is the same in winter/summer. The way they approximate the linearity probably walks with temperature, so there's most likely another small error. Of course - not to give anyone mental whiplash - it could also be that the car just runs richer in winter for whatever reason..[/QUOTE] Right. It's not something I'm losing sleep over. Just something that might be worth mentioning when people come here complaining that their fuel gage doesn't read in much proportion to the fuel in the tank.