The butterfly not working properly. If you manually operaate the lever it should stall the car when in the xlosed position as no air can get to the engine.So if its sticking nearly closed it wont rev up until the butterfly operate
Its hard to explain. If you start your golf up and close the thing the vac goes into itll try stall the car.So alternatively you could actually see if at first start up there is any movement on said arm.You right about the egr though. This might actually not be egr. Id have to go look at my passat to see
If theres air in the first start its getting in after running has stopped. Was running air should be gone. So there would seem air is getting in the system. Maybe a clip or slight nick in a pipe
Looks good to me mate