See also:

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. ...

Do not use methanol
Fuels containing methanol (wood alcohol) should not be used in your vehicle. This type of fuel can reduce vehicle performance and damage components of the fuel system. ...

Fuel recommendations
Use Unleaded Gasoline Unleaded gasoline with a Pump Octane Rating of 87 (Research Octane Number 91) or higher must be used in your Hyundai. WARNING: o Do not "top off" after the nozzl ...