As temps have been dropping outside I have been noticing a problem with my idle after the truck starts. The idle is very inconsistent when the truck is cold. The truck will be running great at the correct idle rpm and the suddenly drop to 300 or 400 rpm, smoke and run very rough. Tap the throttle and the truck will return back to normal idle range. This will continue until the truck has warmed up to about 100 degrees. The wires to the timing advance and their connections are good. Any ideas on what may be wrong.

Paws

 

change you fuel filter to begin with............could be air in the fuel sysem......

was it cold enough to to have jelled?

INj pump getting tired?

just throwing out some guesses out there.

 

Fuel filter is new, pump is about 13 months old, running No.1 fuel and fuel treatment. This problem started last winter upon installation of the new fuel pump. The place that rebuilt the fuel pump says that is what diesel engines do even though it has never done in the seven years before last winter. Does anyone know how the cold timming advance works, KSB???

Paws

 

Make sure you lift pump handle didn't fall down first, I had it happen once, truck did the same thing you described.
Then hope you don't have an air leak on the suction lines.

Ditto, change the fuel filter if you haven't already.