TDI PD misfire at cu

[jhfw]

2004 TDI PD Jetta - Over the past several months there has been an occasional cylinder misfire when the engine has been cruising for about 1 hr. It is unpredictable short lived and then runs fine. In the last few days it has become more noticeable and once the engine is warm it the hesitation starts and continues as if the injector failed in one cylinder. If I turn off the engine and immediately restart it then the problem goes away. Any ideas?

[jhfw]

UPDATE: The VW dealer tells me that there is a fault on cylinder 1 fuel injector – open circuit. They checked it for continuity and it is fine. They also checked the wiring harness that connects to the fuel injectors and it is fine too. I have found some internet references to intermittent faults caused by the TDI PD fuel injector wiring harness. Can anyone confirm this issue?

[chittychittybangbang]

The injectors are electronically actuated and that code suggests what they checked for. Prob not a bad injector. My guess is that something warms up or rubs after an hour and that causes the wiring problem. Probably not the ECU but the wire could be in the injector wire harness or upstream.

[jhfw]

Thanks for the great advice CCBB – As luck would have it, my car was also in for the glow plug recall and the mechanic broke the ceramic glow plug housing in cylinder one so VW is replacing the head. There is a chance that it will come with a new wiring harness – if not I will have them put a new one in. I also asked them to swap the suspect fuel injector with one from another cylinder to see if the electrical fault travels with the fuel injector or stays with the cylinder. The new head should be in Friday so I will let the forum know what happens.