Engine misfire/judder 06 focus tdci - no fault codes

recently bought a 06 focus 1.6, was perfect for 2 weeks then one day it done a random misfire(what it felt like) the next morning while it was cold had no issue had a short drive. Once back in the car and returning home especially when begining uphill it began juddering thudding extremely often. Got home turned it off, went for a drive about an hour later had no issue. A mechanic told me that there was probably water in the fuel, after he asked where i filled up. Put injector cleaner in it and travelled around for thr next 3 weeks without a problem, just once had a slight judder but thats it. Now for the past 3 days it is very constant and very concerning as it is quite a nasty jolt/judder/thud whatever you want to call it. I changed the fuel filter, no difference. 3 different mechanics checked it with the computer and 0 fault codes. One mechanic said injectors, recomended an injector specialist, the specialist said the injectors are fine its an electrical problem. The auto elec is scratching his head and suggested the abs sensor. Basically nobody has a clue. Can anybody please guide me in any way? 02 sensor? Fuel pressure? Glow plugs? How can there be no fault codes? I am so frustrated as i am in a foreign country aswell and dont speak the language and my translators suck. Do not explain things properly