Engine chugging or could call it a surge.

[Refined Trucker]

01 Etech with custom file in ECM. Wants to I call it chug when you are trying to maintain a constant speed with out much load on engine. Like rolling through a 30mph zone on level ground. You can let off a bit or increase throttle and it will quit. Also does it on cruise at highway speeds when terrain doest require much throttle. I am wandering if my ECM is going haywire or if its a glitch in programming. Got me scratching my head. It will also surge the throttle when in cruise and pulling a slight grade that doesn't require a lot of power or coasting down a slight grade will do the same. Its like the cruise is way to sensitive in these situations. Anybody run into this before?

[gearhead204]

you may think I'm drunk but are your drive tires the same size? if you have mismatched tire height like over 2" in circumference the power divider could be causing this.

[Refined Trucker]

Yes tires are matched set. I think I found the problem yesterday. I'm pretty sure one of my new injectors is trying to lay down. Had been battling a intermittent very slight miss and now its not so slight. Noticed wetness around #6 exhaust port yesterday. So I'm hoping its fuel and this is my bad injector. Which is probably the cause for the chugging I was noticing.