Any one know what might be the cause of rough idle , even the gear shift shakes once high idle kicks in , sounds like a monkey is under the hood with hammer when it starts , then the next time idle kicks in everything seems good. Have it booked to get the injectors checked but would like to know if anyone has any other ideas as to what it might be . Only has 48000km on truck. Also gets about 14.5 to 17 mpg figured out tank to tank. The truck runs about 12hrs a day every day and about 250-300 miles driven.