Any Opinions on a 2002 A8 2.8?

[rs200]

my dad have the same car for a 7 years. a8 2.8 30v with manual box !
it is very good and maintanence for it are funny. before few years they done big service (timming belt, pullyes and oils) and this car dont have any problem.
actualy it is the best car that we ever had.
I know that this forum is actualy 2.2 20vt forum.. but I have one question... which one of you didn't open car bonnet for a 3 months ?

[Bowie69]

Me, on my Hyundai, and on my Honda.

Does that say anything about anything?

[geryS2]

pics !

[gunman]

I know that this forum is actualy 2.2 20vt forum.. but I have one question... which one of you didn't open car bonnet for a 3 months ?

Well it looks like I'm gonna have to open my bonnet, most likely followed by an opening of my wallet

The car is really smooth apart from the very slight rev issue which isn't even that noticeable other than the rev counter moving. This is most likely because it's auto so the box is taking up the slip rather than creating a judder. I've read a few other forums, could be a vacuum leak or sticky throttle body. But it idles perfect so doesn't say vacuum leak really.

Car has only done 80k and is mint both inside and out. There's receipts with it for £1000's incl timing belt kit (less than 2k miles ago), gearbox oil service, suspension arms, brakes and general oil services.

Could do with 2 front tyres as there's minor cracks in the walls and the rev issue sorted, then it is as new.

[gunman]

I'm beginning to think the comment about buying cars with head rather than heart may be very true. I'm staring to worry a bit that this rev fluctuation is gearbox slip.

VAGCOM showed up an error with one of the cats, but that could also be either the pre or post cat lambdas. This could be causing the issue as well or it may be completely seperate. I could start sorting stuff out but if there's slip on the box it wouldn't be worth fixing. I don't want to throw good money after bad here.

Has anyone any experience of this sort of thing?

[snaak]

the rev problem is most likely your torque converter in the autobox. Is not a major problem our 4.2 a6 does this too. Did it 2 years ago, still doing it now. Gearbox oil change could solve it, but it will come back. I am not worried.

[Foeglass]

The 2.8 30V engines give errors on cat efficiency pretty quick while emissions are still perfect.
usually you get code 16804 or 16814.

First check if your emissions are still good, if thats the case than check for vaccuum leaks ect. crankcase breather system is made from hard plastic and tends to break easily.
If those are all fine i'd suggest mounting "Lambda / 02 sensor spacers" on the lambdasensors behind the first cat. its a cheap 20 pound fix if you mount them yourself, replacing both lambdaprobes usually gives the same codes..

Snaak is right the torque converter is probably playing up. best solution is fitting a new one but replacing oil and filter can give good results aswell!

[gunman]

Thanks guys.

As a test I came home this eve and started the car and put in nuetral. if I apply a light throttle to bring revs up to about 1200rpm, the car hunts a bit and revs fluctuate the same as when driving on a light throttle.

This car was driven by a man in his 80's for the last 3 years, usually about 30-40mph. I'm wondering if the throttle body is dirty or sticky as it's probably been in the same position for the last 3 years of driving. I'll try cleaning it out and see if it helps, couldn't hurt anyway.