6.6 sorry wrong button Recently I have noticed a louder than normal diesel knock, (almost sounds like lifters) not overly loud though. In addition the truck has become harder to start and longer cranking times to get it to fir, it also seems to smoke (black) more than it has in the past. When its cold or warmed up it does not matter. any suggestions? 88,000 on the engine. recent oil service, and no codes are present. Thanks in advance.