Hyundai Repair: TIMING BELT, proper interval, legal technicality

Question
In answer to your question, the engine is surging to higher rpm's.  The mechanic says this is due to the belt slipping.

Thanks for your reply.
-------------------------

Followup To

Question -
I OWN A 2001 SONATA 4 CYLINDER SEDAN WITH ABOUT 40,000 MILES.  BOUGHT IT NEW.  ENGINE STARTED TO ACT UP TODAY.  TOOK IT TO A LOCAL MECHANIC WHO SAYS IT NEEDS TIMING BELT.  IS THIS COVERED UNDER THE 100,000 MILE WARRANTY?  OR IS THERE MAINTENANCE I SHOULD HAVE PERFORMED?

Answer -
The maintenance recommendation for the timing belt is four years or 60,000 miles, whichever comes first.  If the car is registered anywhere other than California, the timing belt will be your responsibility since you've already exceeded the maintenance interval.  It *is* covered by the 10 year/100,000 mile warranty as long as it's replaced at the proper interval.  

I believe the California exclusion has something to do with a legal technicality.  If the vehicle is registered in California, the timing belt is covered for 10 years/100,000 miles regardless of whether you've serviced it.

Out of curiosity, what's your engine doing?  Very rarely does a timing belt cause an engine to run poorly.  Typically, it either runs or it doesn't.

Answer
If one or both camshafts have slipped a tooth or two out of time, this usually causes sluggish performance (running smoothly but lack of power) on accleration, or stalling or almost stalling at idle when warmed up, or both.  

Your language, specifically the word "slipping," causes some concern.  If this were an ongoing condition like the word suggests, your car would no longer be running.  But if the timing belt has simply slipped a tooth or two, this could be consistent with what you describe.  It's entirely possible there could be a communication issue with the specific choice of words.