E28 M5 not running smooth

[JBHashem@xxxxxxx]

Hi all,

Help me troubleshoot this one:  My 88 E28 M5 is, for lack of better terms 
"popping", "sputtering" mostly when downshifting.  I can smell gas when I 
first start the engine and a bit of smoke appears too (not oil burning).  One 
person offered that I change the plugs and wires and another says that I have 
an imbalance in the air/fuel mixture.  Please help me out.  I am mechanically 
challenged, but will attempt the fix myself...John

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