Need help figuring this one out?? I have an 08, 4500 that I use for towing a 40 ft fiver ( just under 20000 lbs). The truck has 53000 mi on it and tow approx 5000 mi a year, the rest is running empty. I've had a Smarty Jr set on tow for about 3 years now with DPF delete and EGR disabled. The truck has run beautifully all this time---great power, and mileage and when towing I always pull in 5th gear with my G56 trans!! The problem started while towing, I got a double chime, the overhead said "SEE DEALER NOW-- SERVICE REQUIRED" and the power was cut 50%!! (I have an Edge Insight which gives me boost, rail pressure, load, etc and these all drop by 1/2) after the chime, every 8 mi exactly it will double chime again and so on. If I pull over cool down and shut the truck down and start it back up the message is gone and the power is back----for 8mi, then over and over again!!! No dash lights and no codes!! It still drives great on the flat as long as you don't demand more than 50% power!!! I have been getting 2 codes ever since I installed the Smarty Jr, one is turbo speed sensor and the other is insufficient EGR air flow (sorry I can't remember the code numbers) turbo speed sensor has been coming up more often(once every few days of driving), the EGR one maybe once a month. I can read and erase with my Edge Insight. By the way once in a while my power comes back before the double chime goes off again???? Please help---I'm worried about hurting my engine and in 5 days I have to drive 400 mi to home!!!!