Have competent mechanic knowlegeable in EFI systems and equipped with scan tool check your engine. There might be a problem on air/ fuel mixture in case erratic idling occurs. Check the color of the spark plug's tip. If it is black and sooty, the air/ fuel mixture is rich. The color of the spark plug's tip must be brown indicating good air fuel mixture having a stoichiometric ratio of 14.7 to 1.