Hi all,

Mondeo in the shop driving us nuts! Customer complained that the glow plug warning light flashes constantly, starting is harder than normal and a fair bit of pale smoke from the exhaust coupled with poor performance and reluctance to rev.

Car displays fault code P2339 - knock sensor 4 above threshold (neat seing as it only has 1)

We have:
Recoded the injectors (twice)
Renewed the glo-plugs (at customer request)
Renewed the cam sensor (we had one on the shelf so thought we'd try it)
Done an injector leak-off test (fuel looked clean - no debris in it)
Smoke tested inlet system & confirmed EGR valve sealing/operation
Removed battery, checked all earths/relays/fuses
Pulled main loom connector apart, cleaned & reassembled
Continuity tested all leads from main connector block to injectors/sensors etc

All to no improvement. Any ideas where to look next?