# Hyundai sonata gas tank

**URL:** <https://community.cartalk.com/t/hyundai-sonata-gas-tank/46033>\
**Category:** Maintenance/Repairs\
**Tags:** hyundai, sonata, engines, lights\
**Created:** [March 13, 2010, 8:05pm UTC](https://community.cartalk.com/t/hyundai-sonata-gas-tank/46033 "2010-03-13T20:05:07Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![madeaver](https://avatars.discourse-cdn.com/v4/letter/m/e9bcb4/32.png) [@madeaver](https://community.cartalk.com/u/madeaver)\
**Post date:** [March 13, 2010, 8:05pm UTC](https://community.cartalk.com/t/hyundai-sonata-gas-tank/46033/1 "2010-03-13T20:05:07Z")

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I have a 2004 Hyundai Sonata. About 2 months ago the check engine light came on. The shop said the computer showed an oxygen leak, but he wasn’t able to find one with a visual inspection. He reset the light and the car ran fine. The next time I filled up with gas, the car was very difficult to restart (seemed like it was flooded). The car still runs fine, but every time I fill up with gas, I have to floor the gas pedal and rev the engine to get it started again. It seems to be getting harder to start and will die several times before I can get it to stay running. Once I get it going, it never does it again until the next time I fill up.

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**Author:** ![Roadrunner](https://avatars.discourse-cdn.com/v4/letter/r/d2c977/32.png) [@Roadrunner](https://community.cartalk.com/u/Roadrunner)\
**Post date:** [March 14, 2010, 1:53am UTC](https://community.cartalk.com/t/hyundai-sonata-gas-tank/46033/2 "2010-03-14T01:53:38Z")

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The charcoal canister may be saturated and will not vent anymore.

This is usually caused by ‘topping up’ the gas tank.

Only fill until the pump shuts off, do not keep trying to squeeze in more gas.

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**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\
**Post date:** [March 14, 2010, 3:04am UTC](https://community.cartalk.com/t/hyundai-sonata-gas-tank/46033/3 "2010-03-14T03:04:45Z")

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There is a vapor recovery system that is supposed to capture gasoline fumes as you are refueling. These captured vapors are then slowly released back into your engine and burned. Sounds like, in your case, the “purge valve” is open all the time, allowing large amounts of refueling vapors to pour into your engine as you are refueling…

The operation of your “Vapor recovery system” should be checked and repaired. If this proves to costly, at least locate the purge line and disconnect it so it stops flooding your engine. Plug the hose port to prevent a vacuum leak. Be warned, this action may cause your “check Engine” light to come on…