Incorrectly registering Fuel Gauge
Cars affected: Evo 4-7 (possibly the earlier Evo.s)

Symptom:
The fuel gauge is not consistent throughout the range, for example it may drop fairly quickly from ¾ full to ¼ full over 40 or 50 miles and then climb back again to ½ full after stopping. The gauge needle will sink quickly to Empty yet when refilling there is still a lot left in the tank.

Problem and cure:

This is another quirk rather than a fault. The Evo.s fuel tank is virtually split into two halves due to the propshaft and rear diff location (see diagram). The tank has a connection between the two halves however, it can take a while for the fuel level to equalise out after a long run hence the inconsistent readings. Generally try to drive by the trip meter and only use the fuel gauge as a rough guide. Reset the trip meter when filling up and plan to refill at around 320 kms (standard Evo 6 GSR, average driving). Note there is approximately 10 litres of fuel left when the low fuel light is fully illuminated although you would be wise not to rely on this. Do not allow the tank to get too low as particles that settle to the bottom of the tank can be drawn into the fuel system leading to poor performance.

Approximate cost of repair:
N/A