When I hold my cummins in second gear for more than 10-15 seconds it starts puking blue smoke.(looks like mosquito abatement) It also does this when coasting down a long hill in 6th gear. Truck has just over 90K on it.

Anyone have a idea whats causing this and a cure?

 

unfortunately blue smoke is bad news. You likely have rings gone or going out. The fix.... the bottom end needs to be rebuilt...i,e. possible cylinder honing, new rings, new main bearing seals...etc.

If you keep driving it, you're gonna need a lot more work than mentioned.

 

I have great power, no smoke except in second gear and over 2500 rpm. Going down hill in 6th gear smoke only appears once in awhile. I pull 6% grade with my 35 foot 5th wheel on behind with no sweat. I'm thinking it's something else.(hopefully) )