I like to buy gas a full tank at a time, then drive my A4 down to virtually empty (when gas guage in my trip computer indicates I have 30miles or less remaining I'll fill up again). I know it's not good to constantly drive on a low tank, but is what I am doing also bad for my car?

 

I dont see how its bad. I do the same thing have not had any problems.

 

dont do it the problems it can cause could cost +++++£%$£

 

oook... thats really enlightens us all! thanks!!

How could it?? Yes its bad for you to drive the car until it runs out of gas, but that is the issue, running the car until it shuts off from fuel starvation, not simply the tank being low....

 

Yea I have to think that as long as it doesn't completely run out its fine I usually fill up when I reach 60 miles left. Im not "tech certified" but I'm pretty sure thats the point of having a gas tank..

 

Usually i believe most of what you say but without an explantion i dont see how its bad.

 

Every gas tank builds up some sort of residual sediment on the bottom. Could be just tiny specks of otherwise unnoticable particles.
Your engine notices those particles when all those little explosions happen in those things called cylinders, or when going through the injectors. Or so my dad tells me when he sees my fuel light on. When the car was new I ran it down to zero miles left on the trip. Recently I dont let it get past 35.
Seems just easier to keep it above the fuel light warning level instead of causing problems for the car.

 

^^ if you dont believe me then listen to him ( personally I would have thought the answer was simple so no need to go into detail[:-])crap builds up in the gas tank and that's why you have a fuel filter so if you drive it to empty you get all the crap through the system and the filter will fail/block up, on the other hand keeping the gas filled to a sensible level it only gets the good stuff and very little crap

 

As above said, sediments will build up over time and settle to the bottom. When you run the car on empty, the car sucks up a lot of the these particles which can harm your engine. If you ever go to buy a Ferriari or other top tier car, the first two things the dealer will tell you is a) never run your car bellow half full and b) don't let the engine block heat and then cool rapidly and frequently as it may cause it to crack / weaken. Of course, not following these directions isn't going to cause your car to suddenly stop working, but for someone who really wants to take care of their car, its just a few more things you can do to help.

 

I am not sure running on low is bad. You get worse fuel efficiency as you tank becomes more and more empty so if fuel efficiency is your goal, fill your tank when you get down to half a tank remaining. Also I am no expert but I am pretty sure it is very bad for you fuel injectors and fuel pump to run dry. That could be damaging. Of course no one would do that on purpose but if you run your tank down it will happen eventually