okay i did a search but nothing seems to fit my symptoms. it will start surging with the cruise on after about 40 miles. it started when i was having a problem with the pickup heating when pulling my gooseneck. resolved that problem surge went away for next couple of trips. then pulling a small motorcycle trailer with a bike on it 1500 lbs max. it did it again. changed fuel filter still there flow rated and pressure test transfer pump everything good. no check engine light tach bounces 200 rpm speedo jumps 2-3 mph up and down. and you can hear turbo spooling and letting off. had a overboost code. scan tool quit working because of tool problems so couldn't monitor anything while driving. no dead pedal. problem doesn't seem to exist with cruise off. or no trailer behind pickup cruise on. sorry it got long looking for ideas.