My 99 A6 Quattro 2.8L (automatic) seems to accelerate in pulses. When it is cold and I have just turned my car on, I press the gas steadily but the car seems to accelerate in pulses for some reason.

Any idea what might be the cause of this?

Thanks for your input!

 

How long are the pulses? Short? Long? I know mine is pretty steady regardless of temp (i'm in negative ten now). Also, what oil are you running?

 

I'd say the pulses last for a second or two. I have no idea what oil is in the car, I just purchased the car about two months ago (I want to do an oil change, transmission fluid change, possibly a timing belt change, but haven't had the time to get a quote.. Any other maintenance issues I might need to deal with?).

Also, once in a while, I smell gas in the car, not sure what the deal is with that.. :S

 

Well the transmissions are rated for lifetime wear, so you're not supposed to change the fluid. I don't think my tranny has ever been opened since it was driven off the line and that's why, i believe, it is doing so well.

If you're going to be in cold climates (i'm hardly above 0 F anymore), i would recommend a lower viscosity (thinner) oil than usual. I use 10W-40. It lets the engine turn over easier so you can actually start your car in the cold!

And if you haven't noticed yet, there is a sticky thread in the a6 section here called "gas odor" https://www.audiforums.com/forum/sho...d.php?t=120324 It should explain the problem with the gas odor in your car - not a fun thing, but at least you'll know what's going on.

I personally don't know enough to know what would cause your car to pulsate while acceleration though.

 

Thanks, sorry I didn't see the sticky thread.

If anyone knows why my car accelerates in pulses, I would greatly appreciate some info.

 

Sounds like a cylinder missing when cold.. I have a 1996 A4 2.8 that does that. And it doesnt seem to throw an engine light either... Might be it.. Also Fuel pumps when they start to fail act up when cold, so it could be a fuel pressure related issue as well..

 

99 do you get a CEL or any codes on the dash?

 

When was your fuel filter changed? Always start with the simple/cheap possibilities.

 

There are no check engine lights on or anything like that, but when I plug in the DTC code reader, the following code comes up:

Cylinder #1 Fuel Injector Circuit - Open Circuit

This comes up for cylinders 1-6, for a total of 6 codes. What does this mean? Is this an expensive fix?

And I recently purchased the car, so I have no idea when the fuel filter was changed. How would I go about changing the fuel filter, and what would it cost me at a local auto shop?

Thanks for the input!

 

Well I dont know where the filter is on a '99, but on my '01 Allroad (basically A6 Avant wagon), it was located under the car in front of the rear right tire.

I'm pretty sure your car has the same style filter, and its really simple to change. You can pick one up for about $25 at Advance or Autozone. There are two fittings, one on each end...ones like a 17mm and the other is a 19mm (i think). It literally only took my about 15-20 minutes from start to finish when i changed mine.

It's one of those jobs thats not worth paying a shop to do for you if you dont mind gettng a little gasoline on your hands.