When I take my truck on the highway and when I get to my destination my truck smells like burnt oil and only on the highway it gives off that smell. I did not spill any oil on the engine and there are no visable leaks there is no oil in the antifreeze, and there is no anti freeze in the oil, the sparkplugs are clean and the PVC valve is still operational. The engine is noise free and still has good power for a 4 cyl with 98,000 miles on it. I am using Toyota oil (5w 30) and Toyota oil filter. The oil level is about 3/4 on the full side of the dip stick and I just topped the oil off last Thursday. The oil pressue light did not come on there are no trouble codes I really hope it is not the valves or rings. Does any one have any other suggestions.