I have a 2003 F 350 crew cab 6 liter. I purchased it with 112K miles and currently have 121K miles. I recently changed all filters; Oil, fuel filters, and transmission filters, new engine and transmission oil. I added 1 quart of 2 cycle oil to the fuel and I use diesel keen every fill-up.

I first noticed the surge when I added the 2 cycle oil to my 1/2 tank of fuel last week. I drove it to work aprox 40 miles then I filled it up. Today, while I was driving home, I noticed a surge and it also sounded like the truck was miss-firing a bit. THe tone of the motor sounded kind of choppy like a miss on a gas engine. So then, I started up this large hill at 65 mph. The surge happened again. I thought it may be the turbo, but not sure. Well, then while I was on a nice flat stretch, at 65 mph and aprox 1500 rpms and cruizing, the surge and miss started again. Then once I got into town, the surge started while I was at a stoplight. My idle was bouncing around from 500-1000 rpms for about 20 seconds.

I have no idea of how to troubble shoot this problem?

Any help would be greatly appreciated!!!!

Oh yea,

The first thing I did to the truck when I purchaed it was;

EGR delete, Oil cooler, VC9 flush, Coolant filtration system, New FICM from ED with Atlas tune, CCV mod, Blue spring kit, Diesel kleen every fuel up.