W124 dies when it reaches normal op temp

[LikeW124s]

I have a 92 300e. After it warms up, it acts like it is leaned out (it pings or sometimes back fire through the air intake) then stalls when coming to a stop or in slow and go traffic. It's fine till it warms up. Good power etc.
This condition began by the car having poor acceleration after it warmed up. On acceleration it would ping or sometimes back fire through the air intake but did not stall as it does now. Now this condition has worsened to the point where it stalls and will not start till it cools down. Help please. Thanks in advance.