2005 Hyundai Tuscon

Engine Performance problem
2005 Hyundai Tuscon 6 cyl Four Wheel Drive 86000 miles

Starting Thursday when I brought my son home from preschool it started having problems (didn't take it out Friday but took it out again today). Coming home we go around a turn before we turn off onto our road. The RPMs like got stuck. It stayed at like 3000 for a second and then lunged forward. Then when I pulled into the parking lot, as I was about to park, it died. The RPMs went down below 500 I believe. Then today as I took the kids to an Easter egg hunt it died twice more (both times at stops and I think the RPMs went below 500). And it did the lunge thing once too. It tried to died 2 other times but I hit the gas real quick and got it to stay alive. I heard timing belts could cause this as well as alternator issues. Is this true and what else could it be?
March 27, 2010.

Has the check engine light come on? To me it sounds more like a throttle position sensor (TPS), but I need to know if the check engine light is on.

Let me know.

My car does not have any engine lights on. It is hard to describe. It is as if I am driving fine and then as I exit the freeway and brake to stop, the engine doesn't sound like it slows down - maybe sounds like a little rev (but not much). It has also died at a stop sign or when slowing way down (like pulling into my driveway) but starts right up again. I brought it in and they said that there was nothing wrong, diagnostics were fine so they researched online. They said they found that other people who described a problem similar to mine was either the crank shaft or the fuel injector. My crank shaft looked fine so we did the fuel injector and a transmission flush (because another way to describe it that sometimes it also feels like it is skipping gears or something). Well, I don't think it worked. Thoughts?

Jun 24, 2010.
Honestly, I question both of those ideas. Most of the time a crank sensor will just shut the engine down at any speed. Have you checked for vacuum leaks?