I have a 2002 Neon automatic with 2.0L engine. When the car is first started it revs high for a few seconds and when it idles down it runs rough(almost like its skipping). Once you put it in Reverse or Drive it acts fine. When you put it back in neutral or park it revs back up and when it idles down it sounds rough again. There is no error code. When it first stated it was low on oil, added oil and it made no difference. I've talked to 3 mechanics. One said that the timing had slipped(which I thought would affect how it ran in all gears), a vacuum leak(which I also thought would affect it in all gears), and the idle air control(which I was told that if I unplug it and it does not kill the car it's bad). I unplugged the idle air control, no change. I took the idle air control off, no change. I plugged the hole where the idle air control was located, no change. This leads me to beleive the problem is elsewhere. Any ideas? Thanks.