Guys,
The last couple of days I have noticed a strange thing with my truck. While driving at any low to medium speed the truck will surge or sag slightly like I have lifted or pressed the pedal harder. Its very slight, my passengers can't tell that its happened but I can feel it in my foot. It's like your running at a maintained speed and RPM but for no reason it surges or sags. Any ideas?
It's getting cold here in MI and I have noticed a little white smoke on start up so I will be looking into my GP system, but that shouldn't have anything to do with it though, right?
Thanks for any help!

 

Could be the fuel. You are undoubtedly using a winter blend up there. Add a little fuel conditioner to it and see if it helps.

 

Man, I had a thought that it may be a fuel issue too. I have not been able to get to my normal filling station which has a high volume of big rigs so I know the fuel is always fresh. I have in the past used FPPF fuel treatment as a recommendation from a friend that drives a 18 wheeler for a living, is this one that you guys would recommend? Or what do you prefer?
My truck is idling alot more this time of year and I don't really get it out for long runs, mostly short trips to work and being a taxi. Could it being loading up or something like that?

 

On the rare occasion I use an additive I normally just grab a bottle of power service since it's available everywhere, but pretty much any commercial additive that does not contain alcohol should work fine.

The extended idleing might have a role in this. Perhaps the cold oil is gumming up the IPR valve a little bit, in which case a good hard pull may clear it up.