On a 2002 Fiesta 1.4 TDCi I have a sporadic misfire al idle.
No fault code related to misfire(P0380 was stored in ECM),the misfire appear at cold and hot engine...
All injectors was tested and found ok,ECM was updated to prevent any software corruption by other service,the glow plugs was replaced ,no improvement on the car.
At the beginning I checked and cleaned the supply and ground points for ECM ,no improvement on the car(sometime the misfire appear after 5 minutes,sometime appear after 30 minutes).
Only when I captured the exhaust pressure waveform the misfire was revealed...
In the attached file you can see camshaft sensor signal(as reference),intake pressure waveform,all injectors current(for a wrong/missing signal from ECM to injectors) and exhaust pressure waveform:
With this data captured we have concluded that there is a mechanical engine problem at the cylinder 1.
Removing the cylinder head cover the issue was found:a lost bush of the cylinder head cover at the previous engine repair