Re: 2011 powerstroke turbo
It will fluctuate depending on throttle input. Even with cruise control on, if you hit a group of rolling hills with minimal incline the engine will compensate to maintain the set speed. If your on the the throttle manually even a slight movement can alter the engine power as the throttle is electronically controlled and rather sensitive to input. A good test is to put the pedal to the floor and if the boost wanders at full throttle then I would advise the dealer that something isn't correct. It's hard to do with newer diesels as they're a lot quicker these days to get up to the speed limit.
Another thing to try is to keep the engine in a lower gear, and maintain 2500rpm or so. The 6.7L utilizes two turbos: A smaller one for low rpm performance, and a larger one for highway rpm towing power. This allows fuel savings as you'll get more oomph at lower rpm which the transmission will try to maintain. This can potentially allow the boost to fluctuate, although it shouldn't be overly noticeable as the engine with two turbos always maintains some boost on tap over 1200rpm.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!