bstone

So my A6 has never been a speed demon, which is fine, but it seems to be getting much worse lately. Slow acceleration from a stop, and a really have to put my foot into it to get it to go. Once it's going it seems OK. I have recently changed the air filter and spark plugs. There are 2 things that I know are issues right now:

1. Check engine light is on for EGR valve low flow.
2. Transmission fluid may be sightly low due to a small leak at the axle seal.

Other than that, everything else seems to be OK. How significant is the EGR issue to overall performance? And if not that, what other issues could be causing the sluggishness?

Rusty Spokes

The ERG should not be a big problem for performance. Most of the time it is a plugged tube between the ERG and intake manifold..although I suppose the ERG could be stuck "open" and feeding exhaust gases into the intake all the time..which would kill your performance. Very doubtful though.

I would get a Ross-Tech and do pull the codes..a generic code reader is not good enough. Post what codes you get.

Check for air leaks. If someone has replaced the timing belt and did not use the cam holding tool and just painted some marks on the cam wheels..the cam timing can be "off" and the cars will run but not at their best.

Here is a write up on the ERG..for a 1996 A4..same deal as your A6.

https://www.audiworld.com/forums/a4-...ssues-2748634/

bstone

Hi Rusty-
Thanks for the response. I did do a timing belt change a while back when I changed the lifters, but I definitely used the tool. Pretty sure everything went back as it should have, but maybe it's off a little bit? Not sure how one would know, though. The car idles and runs fine, although maybe the idle is a little lower since the change? In my past experience with timing issues on other cars, seems like if you don't have it spot on, it's pretty noticeable... don't know. Even before the TB change, it was never very peppy. As much as I like the car, that sluggishness is starting to weigh on me. With the Ross-Tech, what would I be looking for? would it actually tell me if the timing was out a few degrees? Also- should I expect the car to accelerate better, or is it just the nature of this model and having 200K on it?

Rusty Spokes

With the Ross-Tech or VagCom you can check for codes..sometimes more than one..if you use a generic code reader you may only see one and not others..assuming you have OBD-2..if your working on a 1997

bstone

I have a generic version of the VagCom, along with the cable. Pretty sure I can read-only with my version as it isn't activated. Came with the cable I bought off eBay. I'll check it out and see how far I get. Thanks.

Rusty Spokes

Just an idea out of the blue..could your "change over flap" for the throttle not be working? That is the vacuum controlled part of the throttle. If that is not working correctly then you will be down on power. Check your vacuum hoses carefully.

There is a possible source of problems at the throttle, where the intake meets the metal part. The rubber boot will not fit tightly and you have an air leak there.

On my engines with some high mileage, I used some "screen door sealing rubber" fitted into the gap in the rubber (hard to explain, inside the "V" to tighten the grip) and get a good seal on the throttle. If you take this part off the car..be aware that those two little rubber sleeves that slide on to the metal posts (you can see them in the picture) can drop off and will fall into another dimension or universe somewhere..and be lost forever..keep an eye on them and don't loose them.

marcogyver

I am dealing with a similar issue but haven't found any resolution yet. Like Rusty said and I've read similar things about the leaks between the MAS and throttle body, tears or dry rot on the intake hose. Good luck with your issue.

bstone

Thanks for the responses. Haven't had a chance to run the diagnostics yet, but probably will do that this weekend.

bstone

So I was sort of able to get the codes with my VAG COM tonight. I say sort of, cause apparently my version doesn't do much without activating.. but here is what I got:

P1423- combi port clogged in head
P0170- fuel trim malfunction bank 1
P0173- fuel trim malfunction bank 2
P0171- system too lean bank 1
P0174- system too lean bank 2
Brake light switch implausible signal 00526

I believe after reading up a bit, that the P017* series can all be related to a vacuum leak or leaks (maybe other things as well). I'm not sure about the P01423, and the brake light switch malfunction is as a result of scanning the tranny controller. Although my brake light switch seems to be fine (the brake lights come on as they should)

Any thoughts? I know Rusty mentioned the possible leak area above, which I will check..

Rusty Spokes

That brake light switch code comes up all the time and is not a problem..it triggers because the engine was started without the foot on the brake...it will not cause the check engine light to come on or cause any problems...no worries

Sounds like you do have an air leak