E28 accel problem

[Timothy Alan Roebke <roebke@xxxxxxxxxxxx>]

The acceleration of my 533i has a severe intermittent stumble effect
when the engine is not fully warmed up.
 When warm, the engine is missing some power which is noticeable - have to
'stomp' on it to get a clean acceleration.
 The coolant temperature switches have been replaced (thermo-time tests
fine) Every component in the fuel system has been replaced, as well as
the cap,rotor, plugs & wires.
 I believe it is an ignition-related problem, but cannot locate it. If
there is a bad ground, I have replaced the ends of every ground I could
find. 
 Does anyone have a list of non-obvious things I should check for this ?   

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