I have a problem with my mgt 4.60 motor I keep burning up the glow plug the filliment keeps disapearing and the motor just stalls out. This usually happens in the first couple minutes of running. there is smoke coming out of the exhuast like it alwasy has so I'm not sur if I have the low speed fuel out of adjustment and the high is rich. also what glow plugs should i be using the truck is stock. thanks for the help.