Hey i have a 2010 6.2 scab it has 43,000 miles on it and some times when i go to start it will rev high then back down to low but sometimes when going back to low it will just die . When it is in idel it revs high and back to low alot . The other day i was puting gas in it ( high test only) and it started to sputer so i turend off the truck finshed puting gas in then when i went to start the truck. It took forever to start it was like ther was no gas in it. Sry for such long story but any help would be great thanks and i have also ran lucus cleaner in it.