So my a4 is giving me worst gas mileage than my civic. I'm getting around 14 mpg at the moment. The miles until empty keeps suggesting a higher number (300 miles) than what my gas tank meter has left (1/4 tank). Does anybody know what I should do? I got the car a couple weeks ago and had no maintenance done to it as yet. Does it just need a tune up (spark plugs, oil & oil filter, air filter)? And does the miles left always have a higher number than what's left in your gas tank? What should I change?

Ps. There's a delay when I shift the car into reverse on a warm engine. When shifting from drive to reverse, the car waits about 3-5 seconds then the reverse lights go on and reverse is engaged. Note the lights also have the delay also. Is this normal in audis? HELP!!!

 

First off, are you sure the gauge is correct? These cars are notorious for fuel sending unit failure, and 99% of the time it's a quick fix. Pull the sender out of the tank (there's a DIY around somewhere) and check it - there's a wire on the float arm that breaks or frays, causing faulty gauge readings. Replace the wire with a new one (just solder it onto the points where the existing wire is, and remove the old one), and clean the resistive element that the wiper spans, using electrical contact cleaner. Try it out and see if the gauge matches the trip computer's estimate.

If that doesn't work, scan the computer for any pending codes (or existing ones if your CEL is on). See what they are and post them up. You may need new plugs (the gap can erode with age, so you might not be getting a good burn in the cylinders), a new primary O2 sensor, or might have to clean or replace the MAF. Check the air filter too - dirty air filters will hurt mileage.

Try this stuff out and see what happens. Follow up with any results and we can walk you through the diagnosis.