Car dies when start driving timing belt - Hyundai Motor 2003 Elantra

If it was your timing belt then nothing would work at all

it could be your throttle postion sensor

By you saying the engine "Dies" I am going to assume it restarts.
If the timing belt failed the engine would not start again until the belt was replaced.
So it could be a fuel or electrical problem.

It sounds like the timing belt may have slipped on the sprockets, check the timing belt .

Your timing belt could be broken or perhaps the Drive chain that drives the two balance shafts behind the timing belt

Won't turn over or won't start?

Has to turn over fairly fast

Check for fuel pressure & either spark or
injector pulse while cranking

How many miles are on it? Did you have the timing belt changed at 90,000 miles? Is there spark to the spark plugs? Do you have fuel pressure at the fuel rail? A broken timing belt will make the car sound alot different than normal when cranking.

need to verify that that the timing belt tensioners did not work themselves loose. thus having the timing belt jump timing

it'll either be your ignition system (spark plugs, distributor cap, etc) or more likely your fuel system (most likely your fuel pump or your fuel filter)

It souds like the same problem i had a few months ago, have your timing belt checked, i am most certainly sure that it is the belt, usualy the belt breaks, or slips off the pulley.......hope this is helpful.