22-01-2015, 09:58 AM
More likely it's because the fuel isn't sloshing around in the tank on the motorway like it is on twisty roads, which makes the sender (and thus guage) drop down a little.
1990 Peugeot 205 GTi 1.9 // 1991 Peugeot 205 GTi 1.9 16v // 1992 Peugeot 205 GTi 1.9 // 1999 Peugeot 306 HDi Estate