A6 Erratic RPM when coasting

[wiltona]

Can anyone help? Audi claim to have not seen this before! They have just replaced all the injectors and the throttle body as the car was blowing white smoke and not idling.

the problem now is that the car drives ok and idles ok but now when coasting to a halt the rpm is erratic and the engine surging can be felt.

[nicktooley]

Hi - my A6 TDI does that but only occasionally, no idea what it is although engaging clutch can help as I only experience it when coming to a halt.

[rockydo]

hii i know this is an old post but if it helps anyone else who might have this problem mine does and audi dealer today diagnosed it has throttle adaptor needss replacing they quoted me £300 to fit the part it is going back in tomorrow.

[wiltona]

hii i know this is an old post but if it helps anyone else who might have this problem mine does and audi dealer today diagnosed it has throttle adaptor needss replacing they quoted me £300 to fit the part it is going back in tomorrow.

Let me know if it cures it, I ended up with a new gearbox and torque converter, Before they cured it!

[rockydo]

well car is in audis today and parts are ordered for tomorrrow after noon .i will update the outcome .hope i dont need a gearbox there dont seem to be any gearbox related symtoms sounds expensive i have tiptronic box is that what you had replaced .

[rockydo]

i had my car back 300 quid worse off and yes the problem is still there .i am thinking you could be right about it being the gearbox becuase it doesnt happen in sport or when using paddles in d only .as audi diagnosed the problem and then quoted me to fix it what can i do now that the problem is still there are they legally obliged to fix it now for the price they gave me .thanks again j.

[JonLyons]

I had a very similar issue with the 3.0 tdi tip (05). The best way to describe the symptoms, it felt like someone was squeezing the fuel line for a second and then letting go. It only happened occasionally, the rev counter would bound up and down, one time it cut out. It was in and out of Audi for about a year, 6 months of that it was at their HQ in Milton Keynes! in the end they changed, fuel filter, pump and cable, turbo, ecu, all sensors under the bonnet, none of this made any difference, finally they changed the wiring loom and that cured it. I'm just glad I took out extended warranty

[rockydo]

got car back yet again from audi and after futher investigation they said it is a software update for the gearbox which they did .and yes it did cure it runs perfect now .although they did not mention the 400 quid i spent on a part i didnt need but they didnt charge me for the update .i would have liked them to ask then all hell would break lose lol.