[xccman]

Have replaced oxygen sensor, excess voltage protection unit, frequency valve & spark plugs with little or no change. Upon replacing plugs noticed all plugs on right side of engine were very black and all plugs on left side looked just fine. Any help would be appreciated!!![]

 

[krowbar]

I would check cam timing immediately, you could have jumped the chain. Thats the first thing that came to mind when you said one bank had bad looking spark plugs