Hoping someone can give a little advice here.

’09 Mk2 facelift Octavia – 160k miles
2.0 CR140 TDI

Currently having an issue with my Octavia, turned it on the other day and it started juddering badly (little power/struggled to accelerate). The noise/vibration is the same stationary/moving/idle/under load, and doesn’t seem to be affected by being in gear/neutral/clutch in or out.

Fuel was lower than I normally let it go (20 miles remaining) so topped it up thinking it might be crud from the bottom of the tank and that seemed to cure it. Seems to be a red herring though as I think it was the turning it off and on while filling up that stopped the juddering. It’s now done it twice more where a brief on and off stops the juddering and the car drives as normal afterwards, starting from cold.

My mechanical knowledge is limited, but some googling is potentially pointing to a dodgy injector, does this sound reasonable? Anything else I should be checking?

Did you hear air entering the fuel filler as you unscrewed it? My Passat, and a mitsubishi I’ve owned, caused a vacuum in the tank when low. The Passat exhibited similar symptoms to your car and the Mitsubishi just would not start

Some vehicles introduce a misfire when fuel is low to remind you?

Could be injectors.

But , how old is the fuel filter?
A new fuel filter might be the answer.

But fuel lines / hoses do deteriorate with time, and new biodiesel does attack old rubber hoses.

I’m not convinced it’s low fuel related. After the first time I filled it to well over half a tank and the next morning had the same issue. Might need to go to a garage and see if any fault codes have popped up.

Work mate had an octavia with similar symptoms, no error codes in the ECU either and was fixed with a new fuel filter (which his previous garage had charged for twice over its history but according to the garage that fixed it, looked like the original from when it was built)

“Juddering”

Now is that a misfire or ……?

Is there white smoke coming out of the exhaust?
If so then maybe injectors, if not then probably not injectors.

Also, “juddering” could be an alternator pulley failing, causing the auxillary belt to jump about..

Has it been fed a lot of supermarket diesel in its lifespan?
It does sound like it could possibly be muck related. Perhaps give it a premium fuel fill (V-Power etc) and a proper Italian tune up once the new filter is on?

Has it been fed a lot of supermarket diesel in its lifespan?

Mrs D bought a ex company car from her work. Staff member always used supermarket fuel so he could get club points.

When we bought it, we had a few problems. One mechanic said stop using cheap fuel and use the super diesel to clear it out. (the expensive one)

After the first tank the problems went away. We’ve stopped using supermarket fuel ever since.

Every now and then we add redex too.

I had similar symptoms on an A6 and it turned out (after much investigation) to be the intercooler that had been damaged and had a small leak in it

If it’s the PD engine then could be the injector wiring getting fried as it runs through the cylinder head. Would show a fault code to that effect.