grey smoke, does it smell sweet like coolant? grey sounds like coolant, but if it has a slight blue to it and does not smell sweet then it is oil. also, drop the octane. you do not need to run 93 on something that was designed and runs perfect on 87. you're just wasting money and gasoline. if you have high mileage (above 150,000) you will want to replace the timing chain, i find that they tend to stretch quite a bit!Hello I have a dodge ram 5.9 360 sluggish till 2800rpms and taps in the high rpms and dumps grey smoke while it's tapping new plugs wires cap rotor plenum gasket running 93 octain help plz!!!!!