I have a 2000 Chev K2500 with a 7.4L gas. I use it for plowing snow and when pushed hard I regularly get an oil burning smell. I have had it in to the reapair shop twice now, first time they said it was the intake gaset so I had it replaced for $400.00. I kep smelling it after that and I was then told I had leaky valve cover gaskets so I had them replaced for $200.00. I still get a fairly strong oil burning smell after pushing the truck hard. Any ideas?