Stutters between 1500-1800 revs

[SteveX]

When my engine is cold, and until the temp goes above 75-80c, it stutters between 1500-1800 revs
Another way to describe it might be if you were to change gear really badly, perhaps dipping the clutch to the floor while accelerating. (My car is an auto so it's not that.) I've tried using the tiptronic and leaving it in 2nd or 3rd gear and as the revs get between the 1500 and 1800 it starts to stutter and jump.
Strangely though it never does it in damp or dewey weather, and is actually worst of all on a dry warm day, when driving home after work for instance
It’s with VW to look at it again, for the 3rd time. They've been pretty good with me so far, I know it can be really hard to find an intermittent fault. They replaced the fuel pump first (just before the recalls) and the second time replaced a mechatronics thing (I think that’s what it was called).

I’ve also got real hesitation if you try to accelerate a bit hastily from a standing start or when driving along, and a odd noise 17 seconds after shutting off the engine that sounds like air escaping (a bit like a f4rt) but these may not be related

There’s been a couple of similar threads to this, but this is different I think. Has anyone else heard of something like this?
not Diesel backfire https://www.vwaudiforum.co.uk/forum/s...ad.php?t=38005) or
Hesitation https://www.vwaudiforum.co.uk/forum/s...ad.php?t=41269

[hartry]

could this be the noise after turning off your engine?
https://www.vwaudiforum.co.uk/forum/s...ad.php?t=44794

[SteveX]

could this be the noise after turning off your engine?
https://www.vwaudiforum.co.uk/forum/s...ad.php?t=44794

No, the sound my car makes is more like breaking wind and is a constant amusement to my family. I raised a thread on the sound a few weeks back and it raised a few laughs

[hartry]

have you been feeding it curry?

[SteveX]

have you been feeding it curry?

Not yet, but if it cures the stuttering I'll try anything

[SteveX]

As an update.The car has been with VW since Tuesday afternoon. Yesterday they told me that they had done a 'DIS' report and sent this to Germany. Today they are doing a software upgrade and they're going to update me tomorrow. Fingers crossed

[SteveX]

Update #1,678
The software update didn't resolve the problem. I must admit to being a bit p****d off with this now.
My wife thinks that the cars is about to take-off and won't drive it, and doesn't like being a passenger in it either now.

I've told the dealer, but in truth I don't think they want to see me again (but they will)

[SteveX]

As an update, my Passat is back with VW today. This is the 4th time they've had it now for the same issue. I think they rely on the computer diagnostics too much, as it has never shown a problem.
I have noticed that it shows the problem more in hot weather, when the outside temperature is 24c and above, and the car has been sitting in the sun for a few hours. My worry now is that as the summer seems to have ended, the problem won't be seen again until next summer when the warranty has run out

[tommyweaves]

This is a bit of a guess to be honest, but failing anything else I'd try swapping the air mass meter with another one and see if that makes any difference.

My logic goes like this: unless there's something radically wrong with the mechanical side of your engine, e.g. valves, rings, warped or cracked head, cambelt slip etc. (which you'd know about!) it can only be down to something relating to either fuel, air, or ignition.

Without an ignition system (and assuming you've still got good compression) that leaves fuel or air. If they've checked all your fuel pumps, injectors and software for fuel, maybe it's got itself a bit confused on it's air metering?!

(Pleae correct me gently if I'm talking boll*cks)

[SteveX]

(Pleae correct me gently if I'm talking boll*cks)

I wouldn't say that, even If you suggested a magical wand at this stage.

I'll ask the VW techy if they've considered this and update you.
Big thanks for the suggestion..... this is what makes these forums so good