Rough idle/no rev problem

[boxster]

I had similar symptoms but not exactly. I got engine check light and it started dying whilst I was sat in traffic. I could rev it but as soon as I let off the gas it would either die or seems like its about to die. Problem turned out to be one of the solenoids, and fyi, it is quite expensive. I would try to check them out, although I'm not quite sure how.