x20xev could be several things mate is the engine management light on? either constant or intermitant,
suffer from idle control probs, there is a modified iac vale but when this is fitted u need to carry out a couple of mods to the breathing of the engine, and is a good idea to get the ecu updated to at this time, as youll be using tech 2 to adjust the tps,
but could be a sensor too poss crank or cam!
hope this helps