My '05 MDX will idle rough or surge when at a stop or low speed and will sometimes do it at high speed if shifting gears like when I start to incline, etc. Now, I notice that it does not do this when I turn the AC off. I wonder if it's a bad AC compressor? I had one dealer tell me it was bad engine mounts and the compressor when engaged was jerking the engine and loose mounts. I had two other dealers look at it and they said the mounts were fine. Sometimes the AC will hiss quite a bit from under the dash on the passenger side when I do turn it on. I live in the desert so will need to address the AC issue anyways but wondering if anyone else can relate to this - engine jerking symptoms? PCV valve? other? Any insight is much appreciated!