3.0 TDi [272ps] juddery on start up

**Stevie Wonder** · 22-03-2023,07:20 PM

When starting from cold my 3.0 [272ps] diesel is quite juddery/lumpy for about 20~30 seconds, this seems to have been slowly getting worse over the last few weeks - any ideas?
Once up and running the car drives perfectly - no issues at all.

Thanks in advance,

Steve

**Crasher** · 23-03-2023,02:17 PM

My expectation would be glow plugs but they should come up as a code so it makes me suspect an injector is either coming loose or leaking both of which are common problems.

**Stevie Wonder** · 25-03-2023,01:23 PM

If it were an injector coming loose, would it not do it all of the time?

**OmegaV6** · 25-03-2023,02:59 PM

Originally Posted by Stevie Wonder

If it were an injector coming loose, would it not do it all of the time?

can't answer specifically about audi's as I'm new to them .. but certainly the injector heats up PDQ and will expand and possibly seal any leaks... think about the temps/pressures inside a cylinder !! If it is working loose it will only getw orse overtime .. so worth a check anyway

**Crasher** · 25-03-2023,03:53 PM

Originally Posted by Stevie Wonder

If it were an injector coming loose, would it not do it all of the time?

Only when the bolts fails and the injector blows out taking the fuel rail with it. Sometimes as a clue, a tar like goo will come out of a drilling at the front of the head and drip onto the exhaust manifold.