Misfire - Oh joy

[Newt1]

Chaps. Car has developed what appears to be a misfire completely out of the blue.
Its a funny one as well and could even be clutch slippage...
Driving at 70 is most pronounced, under very slight acceleration the revs increase by 250 or so revs but no drive, then the car suddenly jerks and accelerates normally.
Its only under very slight acceleration, under all other circumstances, eg accelerating from standstill to 30mph theres no problems. Even flooring it from 70 to 100+ is fine, no problems, no jerks, no slippage.
Now for the good bit....you may know already from my other posts its a multichronic and Ive already experience the odd engine judder although nothing too major just every now and then. Ive had it on Vag-COM and no codes at all coming from anything other than the rear window sensors.

Now its actually going in tomorrow for a new timing belt, water pump, serpentine belt etc but Im a little worries it could be a major gearbox issue. In which case it will be time to chop the old bird in and start hunting for a new motor.

Any ideas so I can give the old fella some pointers while he has it to bits ?

I was thinking MAF sensor ?

[Martin F]

Might be worth letting people know a bit more about your car, petrol, diesel, type of engine, mileage etc.

[TapMyHed]

Gearbox would not cause a misfire, as for timing belt....well if this has slipped then the engine dynamics would be a permanent change, not a misfire.

Things to look at (both petrol and diesel)

1. MAF I had a faulty one that caused these exact symptoms. Do not replace with chinese ebay rubbish. Buy a bosch...£60 at GSF.

2. Fuel pressure....worn injection jump, slightly lower fuel pressure...I think this could be seen on vagcom though.

For Petrol, look at cracked plugs, faulty coils and leads....all simple stuff to get at.

Generally, have a look around the engine bay, ensure cables are connected, battery is connected and not corroded at terminals.

Engines are very good, its the 'little' things around the edges that cause the problems (senders, connectors etc)....so look carefully.

:-)

[Newt1]

Ah apologies...

Its a 3.0 V6 Petrol.
75000 miles, 03 reg.

Completely standard, no mods. Taking it down to the garage now. Gonna tell him to hold fire on the timing belt and just do an oil, filter, plug change to see if that cures it first. I'll also ask him to clean the MAF while the airbox is apart.

Damn the bloody dishwasher bust last week, now the car, my wallets getting lighter by the minute ! grrr

[Newt1]

Had 3 mechanics look at this today.
We've cleaned the MAF sensor but it was spotlessly clean anyway, no change.

They all reckon the same thing...gearbox oil and filter change will possibly fix the issue. Worrying thing is it was only done 20k miles ago including a new gearbox ECU by Audi UK.

Going back on Friday to have a service done and to get it on the lift to have a proper look.