I have a 2008 f350 6.4. Motor was just built by kdd. It only has 550miles on it. I had someone clean and flow the injectors before installing them in the new motor. After I drove the truck for about 2 weeks. It developed a hard start once truck was hot it would dump grey smoke on a hot start up. Cold starts truck was fine. Truck drove beautiful no smoke while driving. Had a few injectors that were sticking on hot starts. So I'm changing all 8 injectors brand new from ford. I'm just worried about how the glow plugs look with only that many miles. Plus carbon build up in the glow plug bores what's the cause of this should I be worried I don't want to ruin a brand new motor that's why I'm changing all 8 injectors don't want to take any chances. Any ideas will be greatly appreciated. Thank you guys!