Engine Starts easy when cold but run lumpy for short period then runs fine.

1. Air leak in fuel Line / System

This is a possibility, but since it does not stall, the leak or amount of air in the fuel system was small and engine is able to cope albeit very lump.

Please read the following "Air in Fuel Line / System" for more details from my previous post.


2. Glow Plug System Faulty

If one of the glow plugs if faulty or the power supply to glow plugs is faulty then this could cause one or more of the cylinders to run cold and cause the engien to run lumpy until the cylinder reaches operating temperature / condition.

Please read the following "Glow Plug System Faulty" for more details from my previous post.