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A Result of Bad Gas?

My 70,000 mile 2004 Audi A4 Quattro wagon is in the shop right now with mud in the gas tank - and all sorts of problems as a result. Here’s my question: we filled up the tank and in less than a mile, the check engine light came on and the car started running very roughly. We drove the car 2 miles to the Audi dealer. It took them 10 hours to find the problem. Could the problem have developed any way other than the recent fill up at the gas station? Could it just be a coincidence? Seems unlikely to me but maybe someone out there has another thought. The car has always run beautifully, no problems, serviced at the dealer at all regular dates/mileage, and has not been in any floods or driven through any standing water. The gas station has told us they’ve had no problems. Help!!

“Mud” in gas tank?? Ask to see a sample of this “Mud”. Go back to the station where you bought the suspect gas a buy a sample (5 gallons) and carefully inspect it for contamination.

Perhaps a “friend” of yours introduced the foreign substance to your fuel tank. Is the fuel filler locked?

You told the Audi Dealer the same as you told us (that the problem occured 1 mile after a fill up) and they did not immeditally connect the problem with the fill up.

How certain are you that the Dealer is telling you the truth about “mud” in the gas tank? Is there any proof other than what the Dealer says? Have you seen a sample of the mud? Did they let you look into the gas tank to see the mud?

Ask them why based on your description they did not immeditaly concentrate on a “mud” induced problem.

The big one is are they charging you for 10 hrs diagnostic time? are they trying to mix the diagnostic time in with the labor time? (this may or may not be to your advantage).

It doesn’t look good for this to be a single incident introduction because no other car from the station suffered from “mud”.

Yeah, I agree it depends on what they found was the problem, but certainly a tank of bad gas can cause some issues and require dumping and cleaning the tank, fuel lines, injectors, etc. My diesel Olds had less than 20K on it and filled up in DesMoines at a truck stop. 20 miles out of town it started bucking and finished up the last 80 miles home at about 20 mph top speed. Dealer changed the filter and it was reasonably ok but ended up dropping the tank and cleaning all the water, slime, and gunk out of it. One bad tank can cause a lot of problems. You should have some recourse from the place you filled up so get full info from the dealer and file a claim.

When you filled up at the suspect gas station was your gas tank extremely low on fuel?

If the station was selling gas with mud in it there should have been an epidemic of cars sputtering a dying on the side of the roads in the area. The AAA guys would have been very busy.

If the gas didn’t have mud coming out of the nozzle perhaps there was mud in the bottom of the tank that got stirred up when the new gas entered the tank. Some pumps work at a slow rate, but some pumps are set up to pump a high rate of gas. If this was an especially high flow pump the stream of gas entering the tank may have stirred up mud put in the tank by some vandals days or even weeks ago. Not likely, but a theory.

Of course the dealer could be giving you a line of BS. And the gas stations tank could have been near the bottom and drew mud from the big tank and put it into your tank. The pumps are supposed to be filtered, but there are many instances when the filters have been removed and the pumps are delivering unfiltered gas.