my 2001 i30 seems to idle really fast at startup, around 900 rpms when starting in park sometimes when idling at a stoplight or stops sign in drive. When driving at low speeds, the car seems to lurk when steadily letting off the gas pedal at lowe speeds. I am clueless. Do I need a transmission flush?

 

The car is made to idle fast at startup. This is usually because the engine is cold, and therefore idles faster than an engine that has been warmed to normal operating temperatures.

If you are at a stopsign/traffic light and it is still idling high, I am assuming this is soon after initial startup and the engine still hasnt warmed to normal operating temps? If I am wrong, then you may have some problems, but 900 isnt that bad of an idle, a little high, but can usually be adjusted. The adjustment procedures (not exactly sure about the 2000+) are usually performed when the engine has reached normal operating temps (driving aroudn the car for at least 15 mins).

 

the problem was the transmission fluid was way low, i added some more, and it runs perfectly and imperceptively shifts at any speed.