See also:

What About Gasohol?
Gasohol (a mixture of 90% unleaded gasoline and 10% ethanol or grain alcohol) may be used in your Hyundai. However, if your engine develops driveability problems, the use of 100% unleaded gasoline ...

Check spark plugs and ignition system
Inspect your spark plugs as described in section 7 and replace them if necessary. Also check all ignition wiring and components to be sure they are not cracked, worn or damaged in any way. ...

High-mounted rear stop light
In addition to the lower-mounted rear stoplights on either side of the car, the high mounted rear stoplight in the center of the rear window also lights when the brakes are applied. ...