Rich and lean condition are very noticable in a scope. A fuel rich cylinder in much easier to fire then a lean one. Even with a small drip underload 5 of the cylinder could fire are 30K volts with the rich cylinder firing at 16-18K a lean cylinder might fire close to 40K.

 

Is there any suggestion as to what I should do next?

 

Still no codes? Maybe your going to have to take to a mechainc who has access to a scope.