2002 Hyundai Elantra 2002 Elantra Starting Issues

2002 Hyundai Elantra 4 cyl 146, 00 miles

I have noticed twice today that, after starting, the engine will sputter for a few seconds and then die. When I try again the second time it is OK. So far, this problem only occurs after the car has not been in use for several hours. I have no problem as I drive.

I should also note that a few days ago, I experienced that after starting, the car will not accelerate for a few seconds after stepping on the gas pedal for the first time. After it "kicks in", there are no further problems. This also occurred only after the car has not been in use for several hours.

I took the car to my dealer and they scanned for any codes but found nothing. They checked the induction system and found it clogged up. They cleaned it up and also added a fuel injector cleaner. Things were fine for a few days until today's problem.

My last tune-up was at 117K where they replaced the platinum plugs and the wires. They also replaced the serpentine belts. My fuel filter was replaced at roughly 75K. When I took the car to the dealer a few days ago, I asked if the fuel filter needed to be replaced and was surprised to be told that since it was located in the gas tank, fuel filters are generally not replaced!

Any help would be greatly appreciated as I hope to reach 250K with the Elantra. Thank you.

P.S. Forgive me for this stupid question since I am not a mechanic, but are timing belts and serpentine belts totally different things? Also, what else should I look out for with such high mileage on my car? I recently had to replace all four struts, the intake manifold gasket and the valve cover gasket.