stockncalls
04-20-2009, 19:45
My 92 GMC Sierra 3500 starts and idles fine, then after the period when it would idle down after a few minutes of warming up, it will begin running rough and puffing occasional blue smoke. My fuel is clean, lift pump seems fine, and filter clean. It seems this problem is related to when the engine is going from cold idle to warm, I just can't understand why all the blue smoke because there is no blue smoke on initial warmup period (first few minutes). There is rough running and much loss of power if I attempt to put truck in gear and drive it in this state. If I shut it down and restart, it immediately runs rough. If I shut it down and let it cool off, it will start right up and idle smoothly until the idle down again. During any period when the truck idles well there is no blue smoke from the tailpipe. Forgive me if this is a simple problem but I can't seem to answer my own question after reading through the manual I bought at theDieselPage.com. Any help out there, please?