How many MPB (miles per bar)?

[Krusher]

Originally Posted by 1stToyota

The gas cap says "Tighten" 1-click (not "fill" to 1-click) because if you don't click it the fuel tank pressure sensor voltage will read high and the PCM will assume that someone is driving around with a loosened or removed gas cap.

Ok, time to dumb it down a bit... the CEL comes on for more than just the gas cap being off... or loose.

When the ECM goes into self-check it will run the evap system... if the pressures/volts do not fall within a specified range then the CEL will trip.

The gas cap not being installed or being loose has nothing to do with the evap canister... which can become soaked with fuel when topping off. This also has the potential to trip the CEL. Odds? Probably 1 in a million (est) cars will end up having to prematurely replace the canister due to overfilling.

Lesson? Read the entire post before commenting... and don't top off your tank... that extra squirt or 2 is not worth the cost of a new evap canister.