Occassional, but becoming more frequent smoke on startup, that smells like heavy exhaust. The check engine light is on. Burning oil, but runs like a champ. Made a trip of about 800 miles this weekend that was mostly highway driving and went through about 3 quarts of oil. Around town oil use is nowhere near as bad. Again, truck runs great and very quiet. Switched to full syn about 100K miles ago. I would love for someone to tell me I don't need a valve job and there is some other less expensive fix. How long can I baby this engine and add oil before something drastic happens, and/or can I change oil to prolong or help the valves??