I'm getting 11-14MPG on my 94 A4 Z28. It's pretty much stock. EPA says 15-22, some people say 24+ on the highway.

I know what you'll say. "Don't drive a V8 if you're concerned about fuel economy". But lemme put it this way; "fuel economy" is one thing, being able to make it to destination is something else..:P

What I've done so far:

spark plugs, wires, coil pack, cleaned air filter (K&N).

Planning to get someone to reflash the PCM to increase AFR settings and shift points for better MPG.

What can I do to improve the fuel efficiency?

 

what rpm's do automatic transmission equipped z28's spin at in o.d. (4th) at 70 mph? my (slightly) modded 96 is a 26-27 mpg car on the freeway. interstate 65 from exit 37 up to franklin (exit 68b). real consistent.

 

Keep your foot WAY out of the pedal, I mean don't go above 2500rpm. Have the car scanned to ensure that it is running in closed loop (meaning o2 sensors are working). Scan for any other codes. Check compression on cylinders.

 

Finish fixing the basic mechanical stuff to get it back to stock condition before modding.

miles on cap/rotor? on O2s? on cats?

last time MAF was cleaned?

how do the BLMs look?

 

I used to get mid 20's in my bolt on car. Like others have said, start checking sensors, burnt wires, PCM readings, brakes hanging up, !fat girlfriend mod.

-Dustin-

 

19+ out of a 6speed cc503 car.

 

I get around 18 average in the '97 A4. My driving in that car is 75% highway driving and 25% small-town city driving. That '95 M6 gets much better mileage on the open road (25+) but sucks in town. Of course the in-town mileage sucks because I like the way the loud pedal feels and sounds

 

x2.

 

fuel filter, clean MAF, rotate tires, Alignment, etc

 

@grumpygreaseape: Around 3000rpm.
@MikeGyver: Tried that. Didn't help.
@steve9899: Dunno about caps and rotors and O2 sensor, but I recently changed the cat. Few days after I went over a bump and its never sounded as quite as it did when I put it on.
Pretty sure the last mechanic said he cleaned the MAF, but not sure on that. Dunno about BLM.
@slomarao: Fuel filter was taken care of, again kinda sure the MAF was cleaned to. I do have an alignment issue, but could it make such a huge difference?

 

was there a point that you were getting decent mpg's? has the car gotten worse over time, or has it always used this much fuel, since you have owned it? is most of your driving in town? any freeway cruising to get to work or a lot of traffic jams?

 

everything on and in my motor is new and I only get 15.6 mpg 75% highway. I think I was getting 11 or 12 when I first got it, it had the original opti and wires and spun a bearing. Tune didn't do much for the mpg.

 

Have your transmission looked at, if your car is stock theres no way you should be turning 3000rpm going down the highway. My car doesn't even turn up that fast at normal speeds and I have 3.73 gears and a 9 inch race converter. I suspect either your 2-4 band is slipping or your converter is not locking up anymore. You can check the lock up by driving down the road at a fixed speed, say 50ish. note your current RPM's and without moving your foot off the gas tap the brake with your other foot. this will signal the converter to unlock, your rpm's should go up a noticable amount.

 

my car runs at 2000rmp going 70mph. somethings wrong with your car.

 

i drove my car yesterday to check out the 70 mph/rpm thing, and im spinning at 1800 in 6th going 70. i have 3.42 gears. i know you have an auto, but i agree with the post above sumtin's up with your trans. is 4th gear in an auto a .70 overdrive ratio?