[Rob175]

About a week ago, my 1998 Bosxter w/97,000 miles displayed a check engine light which my OBD2 reader displayed a P0446 code.

I've read that one of the first items to check is the fuel filler cap. To my knowledge, my cap is original, making it 25 years old. So I removed the cap, checked the O-ring in the cap and it looked dry with a number of barely visible tiny "hairline cracks" but no missing sections.

As a "test", I cleaned the metal filler neck where the fuel cap mates to it (lots of black stuff rubbed off), lubricated the cap's O-ring with oil and made sure the cap was very securely tightened much harder than just the first "click sound". Then I resent the code with my OBD2 reader which obviously extinguished the check engine light.

I then drove the car for a couple of days until the OBD2 reader indicated that all car's monitors were in the ready state........since all sensors were "ready", I have driven about 250 more miles over 4 days, in urban areas and on highways.....the check engine light has not returned.

Hoping that the gas cap was the issue, I ordered a new cap, which should arrive in a few days.

Do you think I solved the problem?
(as an aside note I was in the habit of really topping off my fuel tank beyond the pump's auto shut off....otherwise the panel gauge never indicates truly "full"....I think I'll end that practice too.)