Knock on start up and pinging at run temp.

[mercmad6.3]

I have a 109 300SEL 3.5,68,000 mls.It will knock "sometimes" hot or cold on startup,the oil pressure is well within spec. and runs at full pressure even on hot days,idle pressure reads 3 bar hot. I belleive the chain was changed at 58,000 mls. but do these earlier 116 motors have the same tensioner problems that the later alloy block 116's have?
next problem,the car runs great cold,but when hot there is an intermittant miss,at idle the missing gets really bad,but is not a constant miss like a stuck valve,sitting at lights the engine actually stops firing but will keep running if i touch the throttle.When I go to move off at the green light ,the engine stumbles and misses then clears and accelerates as per normal. (fast!).I have replaced EVERYTHING except the block and heads, it's still there.what now?.
mercmad6.3