I have an 05 4wd chevy pickup with 127, 000 miles on it. I could not be more pleased with the performance of the truck. But on Wednesday when i crunk it up the thing started ticking. It has continued to do so every time I crank it up since. Of course this sends fear pulsing through my blood as i fear it has a real problem. Some people have told me that this is common and to run some bg cleaner through it and it will be o.k. Anybody have any ideas i would appreciatte it.