Cummins running ruff

[RTRUCKING48]

(02-21-2016 )ashdan2010 Wrote:  2009 prostar cummins 871 680,000 miles. 2 questions. When I first crank the truck up engine fan cycles on and off is this normal or do I have a problem.
Second thing is when engine is cold it has a hesitation or miss. Rpm doesn't fluctuate, but you can definitely feel it and when she warms up it goes away. Any idea of what can be causing these problems. Thanks in advance for the help.

I also have a 09 prostar with the 871cummins with 677,000 miles and its doing the same thing on the miss and on the fan I notice that when the air pressure is below 90psi fan comes on once it builds more than 90psi cuts off the fan