I'll add another question to this. On average how long does it take for the dealer to do the plug change. My truck just rolled over the 116k mark yesterday and I need to get them done soon. I work a 2nd shift job so I could bring it in the morning. Just don't want them to take all day to do it and I be late for work. As my truck is my only transpertation and don't want to add a rental car to the exspense of a plug change if it is going to take more han a couple hours to do a plug change.