check the glow plugs and the glowplug curcut . also check the fuel filter
Probably the fuel pump. Or the injectors.
is the ecm on a dodge 2001, 2500 diesel hard to replace??
Most diesel engines are hard to start when it is cold. Plugging the diesel engine block heater in will help the engine start.
Hard starting on a diesel is from a lack of fuel or a lack of heat/compression. Air in the fuel lines, plugged fuel filters, and broken electric fuel pumps are the more common hard start issues. Cummins engines use a grid type air preheater. If the hard starting is ONLY in cold weather this is a good place to start.
12-20, depends on the year, and how hard it is driven.
glow plugs
A dirty fuel filter or a plugged fuel line can cause your vehicle to start hard. A dirty air filter can also be the culprit.
By hard I assume you mean not as easy as it used to. It could be the glow plugs which are what diesels use instead of a spark plug or a weak coil. A mechanic could tell you in ten minutes.
Misfires, hard start, no start, more often when wet.
Could be bad glow plugs.
Camshaft sensor is working intermittently, could cause a hard start or no start
thw weather is cold?