RE: GLOW PLUG PROBLEMS.....
Find yourself a hobby shop or order online from tower hobbies or something I know they sell HPI stuff. But the plugs you need are HPI R4 or R5 (thats if its the stock engine), it depends on what amount of nitro content you are using. The more nitro the colder the plug you want, but for the most part in that truck you will want a cold or medium plug. get yourself a few extras. They dont last forever, they can last for months, but they also can last minutes.
Find out what engine that it is thats in that truck, it comes with an HPI K4.6 engine in it stock, but who knows what the other dude put in it. Then go to HPI's website and find out what the factory settings for that engine are, or you can go in the HPI thread here and ask one of those guys, I'm sure someone there would be able to help you with that as long as you know what engine it is. If you post a pic of it I'd be able to tell you what engine is in it.