The car was running well for several days, a couple of decent 100mile + cruises, to Gatwick and back, and a fair amount of local town and short sprint stuff mixed in. All was well.

On the way back from a friends house, en-route returning from Gatwick, I stopped, small top up of fuel (10litres, but only 95ron), and the car would start, but wouldn't idle.
I kept it running with a little use of the throttle, and nursed it 10miles to a different fuel station, the car was a little off.
Filled with 30litres and the car ran fine after.

OK, so I'm thinking contaminated fuel, or the likes.

Fast forward to today.
Full tank fuel, 99ron, 200miles without issue. Got into some traffic, and then it hesitated, and finally (after belching some blue smoke!) ran a bit rough. I stopped, checked fluids, everything else looking normal. Oil pressures good- just under 2 bar idle, between 4 and 5 bar on load, temps are showing oil just above 60/just indicating. Water temp positive indication, but hasn't been close to 1st solid mark on the gauge which I think is 90degreesC.
Started the car, it wouldn't idle.

After a few minutes, the car is able to idle, albeit a little eratic. And the blue smoke had disappeared. OIl quantity confirmed good, and clean.

I didn't have the opportunity to pull the plugs.

My first instinct is the ISV, but how would this affect normal running? The car was a little rough during normal driving. I kept it gentle, fairly low load, max 2500rpm.
Is it possible I have an issue with a crank breather valve? In which case, where is it likely to be.
Fuel contamination? Or filter issues. Well, I am putting it in for a service in December, unless it's forced on me sooner. I'll get oil, oil filter, fuel filter(s) etc. And I want to change the front and rear diff fluids too.

I'm somewhat isolated from any tools, spares, and have no time for tinkering this week (training courses) or indeed for the next 4 weeks. So investigating is not a luxury I have time for.
Any pointers from those in the know, I'd be most grateful.





85 WR quattro
90 V8 Silver, 91 V8 Black, 93 V8 Lago
93 100e quattro V6. Titan, i think