with the ideling try some new plugs..
Mine use to idle from 800 to 0rpm, battery light came on, then it would start back up... i was going about 160kmph (on an open road way out west) and i put it in neutral, the car then turned off... thats scary cuz power assisted breaks and power steering also goes off.
its not too bad now with the new plugs in. also clean the afm and reset the computer.