Intermediate loping when stopped

[Notplayn]

Hello everyone, I have an 08 F350 DWR 6.4

I have a condition that when I come to a stop the truck will start loping for about 8 to 10 seconds then it stops and does it again for 8 to 10 seconds and so on. It does not do this everytime I come to a stop. I do not notice anything while I am driving. Also there is no check engine light or codes set. I have had it at the dealer for three days. They were able to reproduce it but not isolate it. Wondering if anyone else had this problem

Thanks

 

[rick.kellis]

Do you use the Motorcraft cetane booster? My 08 did this running on untreated 40 cetane fuel. I stopped by the dealership and picked up a bottle and it did wonders for me.

 

[08SuperDiesel]

My 08 does this sometimes as well. I use powerservice cetane booster and it sometimes does do it when it is in the tank (I only use the powerservice in the winter). I would be very interested in knowing what the solution is if there is one. Keep us updated.