frenchkiwi

Hi All, new here so bear with me . My 2000 A6 is shuddering at constant revs above 1800, it feels like a misfire. This mainly happens in third but is starting to occur in 2nd also. I have a manual transmission, have changed the plugs and fuel filter (to take them off the 'check it first' list) and it is getting worse every few days. I've also checked the coolant temp sensor and whilst it needed a bit of a cleanup it seems to show the temp on the dash just fine.

Any one have any ideas?

georgeb944

Scan with VCDS and report codes... most likely an ignition misfire... might be a lean condition caused by oxygen sensor. Throwing parts at it without knowing the codes can be a very expensive diagnostic method.

SloopJohnB@mac.com

No…the 'check it first' list begins with a visual examination for broken vacuum lines or nipples/components (free, 5 minutes) then vcds or vag-com scan for codes. You're wasting time and money elsewhere.

frenchkiwi

Ok thanks guys. It doesn;t happen in neutral, although tough to tell without load on the engine. One guy suggested elsewhere it may be the clutch going. Turned out the fuel filter and plugs needed changing anyway, filter wasn't flash and the plugs were a bit gummy.

I'll check the vac lines next. I don't have a vcds unit to scan for codes, will have to try and find one locally.

johnkk

had similar symptoms and turned out to be the MAF sensor. Random misfires per VCDS. But crazy to throw parts at it without a scan for codes

frenchkiwi

One vac hose is a little loose will change it tomorrow. Otherwise the rest are good. I have no way to check the codes so if the new vac hose doesn't sort it looks like its off to Audi for another flogging on my wallet.

Thanks for the help though guys.

frenchkiwi

Ok managed to sort vac hoses, still a little rough but slightly better. As I cant diagnose (no machine to plug in) would be grateful for any more info. It feels like a load issue as when I plant the gas pedal down it runs perfectly, then a little jump when I release. I dont really want to hand it to Audi for a wallet bashing so any help really appreciated :-)

SloopJohnB@mac.com

Don't flog your wallet at the dealer.
Get a vcds at rosstech if you're going to keep the car and stay with audi for additional cars.

johnkk

Your symptoms are different than from my bad MAF sensor. I had fairly violent misses under power and multiple misfire code on VCDS. Nevertheless, try unplugging your MAF and see if the problem goes away. Takes a minute, the MAF sensor is in the large hose going from the air filter intake to the Y pipe.

Get the vcds and find out what's going on, before you assume the service position at the dealer. Even if you don't do the work yourself, the vcds is an excellent BS filter. (My audi dealer is actually honest and appreciates the info, but the VW dealer for my wife's touareg needs careful direction and the protection that the VCDS provides me.

frenchkiwi

Cheers fellas if anyone has any ideas where to get the vcds in France I'd be grateful. I've checked the MAF sensor but didn't try it unplugged. Will give that a go tomorrow.

Agree with the VW thing johnkk, a friend of mine here had the same issue with them. You have to gently push them in the right direction or they'll overhaul the whole power plant.....