2001 A6 Avant V6 Got a company car and did not use the A6 for 6months. Battery died, recharged, started but now bucks as if fuel flow is impeded. Replaced air filter, spark plugs and wiring. Any suggestions would be appreciated. I've run the car for about 2 months now and no improvement.

 

My first thought was a throttle body adaptation, but I believe the car would have done one by now. Do you have access to a Vag-com? Is your check engine light on (should be).

Jeff

 

Do you know if the last tank of gas included ethanol? If so, you might need to drain the tank if it was near full as ethanol can go "bad" if not treated with stabil or other fuel additive. If the tank is less than half full I suspect filling it up might take care of that issue.

I noticed you mentioned you replaced the air filter - but what about the fuel filter? Seems like a logical first step to me - and I might be concerned with buildup on the fuel injectors, but in most casesthat should clear up after some usage.

 

realize this is an old post, but searched everywhere.. how exactly do you drain the tank on an A6? I cant even see the damn thing

 

You should be able to drain the tank in several ways.

1) Old school way: with a hose, long enough that should reach the bottom of the tank.
Insert the hose through the fueling openning and push it down until you feel it touched the bottom of the tank.
Blow the air through it (you should hear bubbles in the tank as the air escapes) to create some sort of a vacuum chamber effect, and then you need to suck in the gas and let it drain in a container.
I haven't done this in ages....but there are two ways to do this.
a) One way is to have a short and strong suck, followed by immediate drop of the hose end in the emptying container you are using, and hope that you got the gas flowing. This technique may entail several tries, but it eliminates the chance of getting gas in your mouth.
b) The second way is to blow the air out, and then suck slowly 2-3 secs before lowering the hose end in the emptying container. This way makes the gas flowing gradually upwards right away, but if hold the suck too long you may end up with gas in your mouth.
It doesn't necessarily have to be a "messy" endeavor as some Internet resources describe it as.

2) You can use a siphoning pump, but the plastic hose(s) it comes with have a tendency to spiral rather than staying straight and stiff. You won't be able to reach the bottom of the tank, unless you replace the hose that goes into the tank with a better, stiffer one.

3) Type in Google "How to drain a fuel tank" and you'll find lots and lots of references leading to various methods involving either the fuel pump; using the drain "****" if the tank is fitted with one; the pressure valve; pressurizing the tank via a drilled fuel cap; or removinf the feeding hose which should be at the lowest point of the tank.

I would personally use the old school method, but I have used it countless times in the past. You may not feel comfortable doing it.

 

Disconnect the fuel filter (you need to replace it anyway) shove a hose over the open fuel line into a secured bucket away from the car and turn the ignition on and pump it out. Have 15Gals of fresh high octane ready to pour in after your done. That will be enough to mix with what ever is left in there after you burn through a fresh tank it should be all gone. If it's a water or crap issue drop the tank and clean it.

 

Easiest way to do it... just dont run the pump long enough to drain a tank that more than 1/3 full at once, take breaks to let the pump cool.

 

oho...didn't know that one, but it certainly makes a whole lot of sense to me.
It sounds as the easiest way too.
I'm still in 1st grade mechanically, it seems.