Hi guys new to the forum and hoping i can find some answers, i know this has been covered many times before and have searched to find a cure for this but still no joy. Story goes the head cracked on my mates MK5 2.0 TDI so far i have changed the cylinder head/bolts/gaskets/DMF/Clutch/starter/coolant temp sensor/x2 second hand injectors and seals on all injectors/injector loom/battery/glow plugs/crank shaft oil seal & tandem pump on head.. Still the car is running a little lumpy on cold start but that clears up and runs fine till warm then idle will drop/run very lumpy and cut out, when trying to restart the car will maybe start after 45seconds but again will cut out unless the accelerator is held down a little. Even while accelerator is held steady the revs will go high/low very slightly. The car ran fine with no probs after the head rebuild, this started a month after, any ideas as to what problem might be?? VAGCOM shows no engine faults.