Help me cure a random miss fire/rough tick over on idle please.
I'm almost at my wits end with this now, my car has been suffering from this for months.
When you cold start the car it starts and runs perfect, if you get the car up to temperature then that's when this rough idle/misfire intermittently occurs. I can pop the bonnet and you can hear and see the engine shaking/missing.
When cold and warm the car drives perfect but just to give you an example of when this happens, I'll be coming back from Wakefield on the M1/M62/M606, I'll get the end of the 606 and waiting at the lights on the slip road and it will start to shake and miss, once I set off its perfect again, the car drives perfect whether hot or cold but only idles rough when warm.
I have replaced the injector seals, replaced the fuel filter and temporarily blanked off the EGR valve, timing is correct, injectors have been checking in VCDS to see if they are firing correctly and the car still does it!
What else is there to try now? The car is throwing NO errors up on the ECU, I wish it would but it's not. I'm getting close to taking a can of petrol and a newspaper to it.
The car is a 2.0L TDI 140, manual, 57K.
What can I try now? Please help.