bucking & surging at speed

[67caprice427]

Howdy, I'm looking for a little advice. Bought a 1028 about 6 months ago, and I've put about 5k miles on it since then. It's always cranked and ran fine until coming home this afternoon. I was running about 50ish, when it felt like I kicked it into passing gear, and after that, it was bucking and surging if I backed out of the throttle. It seemed to run better at higher rpm's and it cleared up a little, as long as I kept a steady speed, this went on for about 10 miles, with no smoke or gauges lighting up. When I exited the highway, it was back to running normal. Would this be a sign of a failing lift pump, or fuel filters needing changing, or ?????????????? I really don't want to break down on the road, and I can fix it at home now, if I know what it is. Helpful advice wanted, thanks
BTW, truck only has 24,500 miles.

 

[rsh4364]

My 1009 did this once,it was short piece of rubber line feeding mechanical pump.As it aged it kept sucking in on itself.Would also change filter and add an inline fuel pressure gauge.

 

[loosescrews]

I had my truck do this, and it ended up being filters.

 

[CUCVLOVER]

My truck did the same thing. I needed up having to ditch the box filter for a spin on. My filter base started sucking in air so I got rid of it. To determine my filter was bad I used a small clear inplace of the stock unit and all the issues went away.
Hope this helps.

 

[MakersTeleMark]

If you are going to change the filter, which I highly recommend, do yourself a favor and pull the pressure sensor and plug the hole in the back of the housing while you are at it.