I'm not clear on the timeline, but regardless, when you disconnect the battery, the Engine Computer loses its memory and has to relearn "minimum throttle" before it will know when it has to be in control of idle speed. Until then, it may not give you the nice "idle flare-up" to 1500 rpm at start-up, it won't stay running unless you hold the accelerator down 1/4", and it will tend to stall at stop signs. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the pedals.
For this type of noise, a stethoscope is the tool of choice. All auto parts stores sell them, and you can find them at Harbor Freight Tools for about five bucks. For a mechanical whining noise, start with bearings in the idler pulleys for the serpentine belt. For a whistle, suspect a vacuum leak.
Monday, February 17th, 2014 AT 8:15 PM