I've had this issue for some time now, when the car has been sitting for about 4 hours or more when I start it up it judders when driving for the first few mins of driving. If I leave the car 8 hours or more its really bad, if I leave it out of gear and rev it misfires quite badly and for the first 5 mins of driving it drops power very badly and judders. When the car has been running a while its normally OK although I get the odd misfire it feels like.
I recently had the glow plugs replaced to see if that would sort the issue out, unfortunately it didn't. Annoyingly when I was replacing the glow plugs I snapped one off in the head and that resulted in me getting a garage to remove the head to remove the plug.
My next thought was that air might have been getting into the fuel line some how, but I have checked the fuel lines and can't see anything wrong and replaced the gaskets at the fuel filter to no avail. As it judders for so long it seems to me to be unlikely to be air.
My next thoughts were either the glow plug relay or a faulty injector, I don't think it would be the relay though as it makes no sense why leaving the car for longer periods would make the problem worse.
Please let me know what you think, do you think it could be air or is it more likely an injector? How much would it cost do you think to check \ replace the injectors?