BMW Repair: Occasional idle stalling + occassional judder/hesitation, hesitation problem, cam shaft

Question
Problem 1. I have a 1997 BMW 523SE, occasionally when I am at traffic lights it will stall or the revs will dip and then come back up again even though its in neutral

Problem 2. There is an occasional judder/hesitation when driving, its intermittent and sometimes will not happen for a few days or happens 2-3 times in a few hours

Action already taken

ICV taken out and cleaned thoroughly
Full diagnostic check run and cam shaft senor error came up, so new camshaft senor has been installed

Please help as its driving me crazy


Answer
I never heard of a 523se. What country are you from? I would think however the electronics are similar to USA 528i. Is it an m52 engine?(6 cylinder 2.3L gasoline with VANOS on the intake camshaft). The fist problem sounds like a cam sensor but they did not commonly fail on those engines, unlike the newer ones. The second problem sounds like bad coils. Have new spark plugs ever temporally fixed the problem? Please get back to me to update.
                 Kimber