newaudi03

Hello i have a 2003 Audi A4 Quattro with the 1.8T engine and i've been getting really bad gas mileage. The car is at 162k and i'm getting just barley 200 miles to a tank which is completely ridiculous. i drive 80% city and 20% highway. In the city i get 13-15mpg and on the highway i get 21-23mpg. I don't drive the car hard unless i'm getting on the highway or passing someone, etc. I've cleaned the MAF, throttle body and all tires are at 38psi. Im also running 0W-40 european blend Mobil 1 full synthetic oil. I'm not sure what else to do, i'd like to be getting almost 300miles to a tank. Any help would be greatly appreciated, thanks!

TheCJ

could be all kinds of things at higher miles. 02 sensors, lower compression, bad plugs, restricted exhaust, sensors like water temp sensor reporting incorrectly...

A1EK

how long does your car take to warm up? could be a bad thermostat which can make a big difference as the car takes longer to reach operating temp.


PS 38PSI !? thats quite high is it not, is it not bumpy?

TheCJ

Actually my specs say 40PSI all around as standard and heavy load was higher, probably for fuel economy. The ride is nice and comfy, wish I could feel the road more... thinking of getting hard racing shocks because I like the feeling of the road.

A1EK

Maybe I should put more pressure in mine !


How long does your car take to get to operating temp? If it takes more than 5 - 10mins I would say this is too long.

TheCJ

Yea, I try to follow the manufacturer spec since under-inflating can also cause sidewall wear and potential blowout. The best is to follow the chart that is on the inside of your drivers side door (at least mine is). Also the users manual should echo that if you had a repaint and the label is damaged/missing.

As for operating temp, that's very variable. The tire inflation specs are for cold tires so just check them first thing in the morning on a flat surface. To get to hot, maybe 30min on the highway but don't worry about it, cold temp is better because if the inflation is unbalanced you will get heat buildup in the tire anyways. 30min to heat the car is my rule of thumb for oil,trans,rear diff oil changes.

A1EK

I was just refering to how long the engine took to get to normal operating temperature with the needle in the middle etc.
IF your car is taking 30 mins to get to this temperature something is wrong and will definately be a factor on your MPG's as the ECU will not be adjusting the fuel and air mix correctly as you use more fuel on a cold engine start. My car get to operating temp a highway from about 5 mins to 8 mins, normal roads maybe 8 mins to 12mins but not 30 mins !

TheCJ

Ah ok, no my engine heats up fast enough, I was thinking tire temperature operating temperature. They don't get very hot very fast but on a longer drive they will get nice and warm. I usually drive 30min to get my engine fluids stirring to do fluid flushes and scavenge as much junk out as possible. All of this about tire temps is kinda irrelevant actually. Hands down the proper way to check pressures is cold.

audiyadosir

My 2005 A4 B6 is getting 11 MPG consistently in San Francisco and I want to drive her into the Bay because of it. I'm able to get about 23-24 on the highway...I just never drive highway...always city, hills, traffic.
I bought her used and although I expected to inherit someone else's headaches, I was a bit surprised at the low MPG. Sooooo, I did what any new-used car owner should do...made it mine. I changed the air filter, the fuel filter, the oil and flushed the coolant. I changed the spark plugs, added fuel injector cleaner to the tank several times and I even changed the front brakes including new pads and rotors. It seems like the right front piston may be sticking in the caliper or the ABS module is sending a bad signal and I'm getting too much pressure on the brake pads? I dunno. The squeaking got so bad I had to change the pads and rotors on a whim because I had the time and the budget (sorta), but it's been more than I could handle.

I even started driving my car like a little girl would with practically no revving or turbo. What kinda fun is that? None. So, with that trick, I got 11.6 MPG and that's when I stopped driving caring, started driving her more like a little girl with intermittent aggression and Uber-fury. If I'm gonna feed her 91 octane fuel and still get crap mileage I'm gonna at least have some fun!

I'd love some ideas on why my brakes squeak and I just put them on there? Why does the front left brake start a rhythmic squeak after she warms up?? I checked the fit and the alignment of the bolts and screws and it all seems fine, yet she squeaks. I'll check the ABS module and I also read it could be the brake servo. I have no idea what the brake servo is, but about a year ago I didn't know anything about cars at all. I'm a quick study with the drive of an Audi. Any other suggestions would be most appreciated. Cheers!

lyleswk

Here is a random thought. Maybe your emer brake cable is stuck causing the rears to drag.