Got a bit of an issue with my '04 CDTi (120). Was low on fuel yesterday, so filled it up at Tesco (I know, I know - don't judge me - I like the Clubcard points!). Drove to work (40 miles) with no issue, returned home (another 40 miles) and seemed ok except I did notice a touch of lag on the acceleration, but it was very slight and I didn't really pay much attention to it.
Got home, did the 3 S's and left again for the missus' place. I pulled off and noticed there was quite a bit of lag. I got to quite a busy junction, went to pull out and it just lost loads of power and stalled. Started it up again ok, went to pull off again and it just stalled - not a violent stall, just a severe lack of power. Started it again, revved quite hard this time and managed to keep going but with very very jerky acceleration. This did smooth out, albeit with a lot less power than I'm used to so I decided it was best to return home.
A friend of the family is a mechanic, so he kindly came over and checked the hoses and plugged in the diagnostics kit - he couldn't find any problems at all, no error codes with the engine, turbo etc. Did a bit of a test drive and it didn't do the jerky thing, but it did seem less powerful. He suggested that it may be a tank of bad fuel - maybe even water from a condensation build up from an empty tank at the station.
I started up this morning and got to work ok, but given the frost I left the engine on for a few mins whilst scraping the windscreen before I set off. Again, I felt the lack of power but it was ok getting to work. Seems to be ok once up to speed in terms of response. Just went out for lunch now, started it up and drove off and it did the jerky thing again.
Seems quite a coincidence that this has started to happen after I filled up, but then there's also the fact that the weather has changed to very cold so I'm wondering if there's something else that could be going on that wouldn't be picked up by the diagnostics.
I'd rather not have to take it back into a garage to get the tank pumped, so I'm wondering if this sounds very symptomatic of a tank of bad fuel and if it is what's the best thing to do? Fuel conditioner, diluting it with high-octane? It's worth baring in mind that it's only been about 6 months since my last service during which the fuel filter was replaced.