I have had this issue too except sometimes when the engine is warm it still happens. It was happening when I bought it with 35,000k's on the clock, changed the battery at 50,000k's > no change. I am told I am due for new spark plugs now (at 90,000k's), so we will see if that helps. I am not optimistic since the spark plugs should have been fine when I bought the car. Any other possibilities.... starter motor???