My 2001 hyandai elantra idles high (1500 to 3000 rpm) when started and when shifting gears. The check engine light is on and the code points to a misfire on the second cylinder but new plugs and wires didnt work. Is this most likely a idle air control valve, MAP sensor or throttle psoition sensor

First thing check for engine control module fault codes, if you have a lean running code then you have a vacuum leak on the engine, this allows air to bypass the idle speed control system and raises the idle up. Another issue is a sticking Idle speed control air bypass valve, but that is not common and vacuum leaks are.

Check the level in the ******. Make sure that oil is there and topped up if necessary. It should be on the upper marks. Good luck.

I think you have answered your own question here as modern cars use a computer to change gears and their is a big electrical plug on the side of the gearbox and its highly probable that this plug is wet ,it should dry out after a couple of days hopefully if not you will have to jack the car up and disconnect the plug and blow it all out with a airline but just a natural drying process should do the trick

I'm not that user, but go to Autozone and have them scan your computer for the code to your check engine light. It will point you to which sensor to replace, as this is likely your culprit. There are two speed sensors which are critical to transmission shifting on this car. The one I'm familiar with is on the passenger drive axle, but when mine went out (I have a 2001 Elantra as well) I didn't have any of these issues you describe. I don't know where the other sensor is, but that's where I'd suggest starting. Get it fixed quickly though, the web-boards I've read warn that these symptoms can be pretty ******* this little transmission. Good luck!

Shift senor upper just replaced mine $65.

check your idle control valve and sensor may need replacement

could be a lot of things. I personally would start with your vacuum lines... check for a leak somewhere. You can do that by spraying carb cleaner (if motor tries to die, you found your leak), or it could be a sensor, likely idle air control, mas air, etc.)

weeeeiiirrdddd. i have a 2001 hyundia elentra gls, and my third cylinder is misfiring as well. my car also revs constantly on idle and in between shifting. it will flutter between 2-3000 or it will just stay at 5000. i replaced my plugs and wires to no fix with my cylinder. autozone also told me that it sounds like my throttle position sensor needs replaced, but every part they try to sell me will not fit and they swear up and down this is the right part...

your shifts correctly, as your driving it downshifts and stay stuck at that gear when u stop and try to take off but intell u turn off your car and restart it it shifts correctly intell a few mins later. i am thinking that is a speed sensor (out signal problem) mounted on top of your transmission next to the battery tray, you will see couple of cable linkages next to it ...

The code says tps switch so replace the throttle position sensor.