The engine sometimes hesitates when accelerating, or even when it is already running at highway speeds. It also hesitates sometimes when going about about 30mph. Spark plugs have been replaced. Check engine light sometimes goes on and off on its own. Fuel additive has been used also, it caused check engine light to go off, it still hesitates.

SOURCE: acceleration hesitation

Depends how long since your last tune up and mileage. I would do a normal oil change, oil filter, air filter and plugs. If she still does it, try checking for a vacuum leak. Start the vehicle and spray "lightly" carb cleaner around your vacuum lines. If you have a leak the engine will increase in idle suddenly. Replace the line or part. AS A LAST resort and pretty rare is the distibutor. They usually run about 75.00 to 110.00...hope this helps.

SOURCE: 2000 Hyundai Accent will suddenly stall and wont restart

Have someone check the idle sensor. I had to have mine replaced along with another that I don't remember which one is was.

SOURCE: My 2002 Hyundai Elantra Gt (2.0L)engine runs rough

The Hyundai online shop manual and my newly arrived Hyundai shop manual kept pointing to the coil as a possible problem. While preparing to check coil continuity I discovered the pigtail connected to the bottom of one of the coils was loose and the contacts were burned. This is the coil that supplies spark to plugs 1 & 4, the same ones that kept showing up each time the check engine light illuminated. After cleaning the contacts and making sure the pigtail was securely attached to the base of the coil I have had no further problems.

SOURCE: 2000 Subaru Outback

It sounds as if you have a brake or c.v. joint problem. If you haven't checked your brakes check them first (cheapest to repair). Ifbrakes are fine c.v. joints are most likely the problem. When checking brakes if doing yourself check inner and outer pads as well as rotors for scoring. Good Luck.

SOURCE: Acceleration Issue

your fuel injectors are clogged