[thstone]

Originally Posted by Jgkram

I don't use the heat/cool system a lot. My area is pretty temperate most of the year so not really necessary. However, when I do turn it on (especially the ac) it seems to overload the engine. By that I mean the idle will definitely drop and it will idle more roughly. Not to the point of cutting off but definitely not smooth like when the system is not engaged.

Again, is this normal???

No, this is not normal.

Originally Posted by ianacole

Older cars have an A/C idle valve, or something along those lines that kick up the idle when the A/C is turned on. Do the Boxsters have anything similar?

Yes, the ECU will adjust the idle control valve to maintain a constant idle speed even as the engine load varies. The idle might vary a bit at A/C turn on/off when the load changes abruptly, but should quickly settle back to the normal rpm and maintain it.