losing RPM's when starting PT cruiser

[bnichols9883]

For the past few days I have been having some problems with my wifes PT cruiser. It naturally idles around 1800 RPM, here lately when you start the car it jumps to 1800, like always, then drops to 500RPM then bumps back to normal. This cycle continues many times ultimately either becoming normal and driving fine after 2 min, or it dies then I restart it and begin the process. I dont know what could be causing this, my wife told me this morning that it now has a funny smell. I have not checked on that, and it may be all in her head. But if anyone has any insight on this topic I would greatly appreciate it.