Touran 2.0 TDI judder and power loss - code P0272

Hi I'm new to this forum so will try to be as concise as possible but lots to try to explain which may help diagnos ethe problem.

Bought 2nd hand 2006 (56) Touran 2ltr SE TDI a few weeks ago, privately. Test drove, seemed totally fine, no warning lights on, lots of paperwork and full VW service history up to the last main service in July this year.

Drove down to Croyde, North Devon from East Sussex last week on holiday with the kids and car was totally fine on way down, no problem. Three days into holiday I was on a day out driving up a pretty steep hill (Croyde Bay up to Saunton Sands) when I experienced dodgy juddering and power loss on accelerating. Carried on driving towards Braunton and it seemed to continue with the judder when accelerating. The judder got so bad at one point the entire car was vibrating, seats going the lot - all stemming from the back of the car. It appeared to happen between 1500 and 2500 rpm.

Managed to get to a local garage and at this point no warning lights had come on. I parked up and switched engine off

Guy agreed to take a quick look as he could see I had the kids and missus with me.

He took for a drive for approx 7/8 miles, up to 60mph, through the gears, slowing right down etc and no judder or power loss, no wanring lights on etc. Popped the hood back at his workshop and could not see anything visual that could be causing it.

He took oil cap off whilst engine was running and said it seemed odd that it was blowing so much with the cap slightly off as it should have been sucking the cap down.
With engine off he removed oil cap completely and said the vapours coming out the engine were odd, but didn't smell oily.

He offered to do a proper diagnostic if I wanted (cost £30+vat).

I said I'd see if it did it again first. Anyway, drove off back to holiday cottage and all seeemed ok but popped into Tesco enroute. Leaving Tesco it started to do it again all the way back to holiday cottage.

So I called him up and booke dcar in for next day. Turn out his diagnostics threw up no faults or error codes and he had test driven again and couldn't reproduce problem.

Picked up after shelling out (£30+vat for diagnostic and £35 for his time).

Drove a few days later and all ok.

The day I left, the juddering and power loss happened yet again. Had long drive to Bristol ahead, so I pulled into a local petrol station in Braunton again, tried the old, turn off and on again and it did seem to do the trick. Then about an 40 mins down the road, started again. Made it to a friends in Bristol overnight.

Next day left for Brighton and yet again the juddering and power loss started shortly down the road. Again, no warning lights (and bear in mind this was still the same tank of fuel we had filled up from Brighton 6 days prior).

Carried on driving and on the M5 seameed like I could power through the judder as long as revs were way above 2500rpm so no 6th gear, had to stay in 5th so fuel consumption was nuts. By this point was getting worried weather driving it was doing more harm.

Anyway, pulled into each services on M5, stopped and started but this time the problem kept happening, then enroute to Reading service I got the Emissions Control Light on solid in the rev counter and message saying "EMISSIONS, GARAGE!".

So ended up getting recovery. Before they towed he tried to diagnoase and was getting up fault code P0272 on his cheapo looking machine, saying problem with cylinder #4.

I've just spent literally hours reading forums about this as I don't want to get fleaced by my local main VW dealer. Can't seem to find anyone with the exact same problem though. There are lots similar but often they end with no solution. I don't have a warranty either.

I also currently own a 52 plate golf 1.9 TDI and have never had any problems like this so assumed these enigne are work horses.

Looks like this could be a common(ish) fault and that VW are uselss in helping. But lots of forum posts suggets that replacing injectors doesn't necessarily fix the issue?

Can anyone help me?

Are there some simple (cheap) things I can do myself to rule out before I go down the route of a VW dealer charging me to replace injector #4 (and the other 3 more than likely)?

I have read some posts that some of these 2ltr TDI engine were recalled for injector replacement (Piezo injetors Injector recall - yes this is really happening at last!!!!). I have no idea what mine has?

Have also read it could be a sensor or wiring fault and there may have been a recall for some wiring loom too?

Thanks in advance