Engine light is on

[quote:0f5c5c8d6c="jknmodels"]2002 Hyundai Accent, 120,000 miles

The engine check light goes on then off. (Stays on for for about 50 miles then off for about the same)When the light is on, it is almost impossible to fill the tank with gas. When the light goes off the tank can be filled without any problems. Any ideas?[/quote:0f5c5c8d6c]

Wow! This really doesn't make much sense, does it? After all, a fuel tank is just a tank. The only think I can think of is something which a mechanic told my mother regarding her Toyota many years ago. The mechanic suggested that my mother never let her tank go much below half full as the tank's internal baffles could collapse. Apparently fuel tanks have baffles to prevent the gas from sloshing around.

I guess the symptoms you are seeing could suggest that the tank's internal baffles have collapsed. This then could cause problems for the fuel pump (inside the tank) when trying to draw fuel from the tank. That in turn could be causing the check engine light to come on intermittently.

This is all just a guess; hopefully somebody else with more experience will chime in with a better answer. :?

You need to find the code in the computer for starters. Probably a "PO440" as a guess. The evap system uses vacuum or pressure to run the self tests or monitors. It tests for leaks , soleniod operation, valve operations.