First I think that they were trying to relate to the fact that we never refer to our Jeeps as cars. They don't really fit into any category other than Jeep. As far as pricing goes, 4Wheel Parts offers to beat any price so check them out. The rpm issue is something that I haven't dealt with and I thought that you might be referring to another problem that I have encountered with my 06. I hope that this helps a little. Please be patient and I am sure that someone will address that rpm issue for you.
Oops I almost forgot pulling the code.If your CEL (check engine light) is on you csn pull the code to find out what the problem is. Even if the light is not currently on, it will show any stored codes that exist. You can take the jeep to any autozone and they will test it for free or you can pull the codes yourself. To do so, turn your key to the on position (not start), then off, then on, then off, then on and leave in that position. You will begin to see the codes in your odometer window. When all the codes have been displayed it will read "done". Go to this site to check the meaning of the codes.