2001 Hyundai Santa Fe Tough problem. High idle problem and

Sounds like your having the same issue I am. Since I am having the same issue, I am assuming that it is safe to say that the temperature sensor is the lead cause of the problem (cheap sensor) but hard to find. I am still looking for the sensor. I found one site where it told me it was located under the ignition coil, so I need to find that now. It's just hard to move around under the hood of these cars.

Ok, so I found the temperature sensor and got it replaced and now my check engine light is off. My car started with no problem, fan doesn’t kick in all the time, no jerking, no high rpms; she's purrin like a kitten. This is for everyone else if you need to know where the temperature sensor is on a Hyundai Santa Fe:

When looking at the engine from the front of the car, look to the right side of the motor. You'll see the radiator hoses (top one, then bottom hose right next to each other). Put your hand on the lower radiator hose and run it underneath and toward the motor (still underneath the hose). Now between your hand will be the lower hose (above your hand) and two other lines (below your hand). As you move toward the motor you'll find a plug...That's it. You can't see it from above, but it's there. Use a 16mm deep socket to get it out (after unplugging it). Be careful, because water/antifreeze does come out and if you just were running your car it will be extremely hot. After replacing the sensor don’t forget to fill back up with water (only about 1/2 gallon or so comes out). Well that's how to replace a Temperature sensor on a 2001 Hyundai Santa Fe.