I get 250+miles to the tank, and I floor it at LEAST twice a day. Recently, I Richened up my fuel with the predator, and now I get 200 miles to the tank. Do you think if I change my timing, that'll improve mileage?

 

i got a 98z and i've been having problems with my gas milage also... to a full tank which just over 15 gallons i get anywhere from 200-250.. last tank ful i did nothin but highway and only around 250 miles at empty tank..so if you calculate that its 16 miles to a gallon on the FREEWAY...what you guys think it is with mines... i used be able to get 300+ before i hit 60k now im at 66k changed pugs wires and fuel filter and ran some redline fuel injection cleaner through no help.. i had my fren scan the car and didnt bring up any codes for the 02's being bad.. my next action would be getting the fuel injection serviced by the dealer?
also he did say my timing is at 20 something at idle..is that normal?

 

Hey v10power, as for the steam coming out of your tailpipe when its cold is just condensation. Its the same thing as if you were to breath into really cold air. The exhaust is really hot and all of a sudden is dumped into freezing cold air. ITs normal and where i'm from i see it all the time in the winter unless the car has been running for a while.

 

Ouch that sucks that you are getting less then 200 miles per tank.. Damn my 02 Z gets from 220 - 260 out of 3/4 tank w/ combo of freeway and city driving (which more city driving then freeway).. When I was driving 65 miles one way to work and 65 miles back, I did get 375 out of a tank of gas but I could have gone further but I did not want to risk it, though.. Plus when I drive on the freeway I cruise @ 80 mph and romp on it @ least 4 x a day when I drive it... So it has to be w/ either bad 02 sensors or something... I am not sure if it would be expensive to check the 02 sensors but you can always check around at different shops and even see if your car is throwing a bad code.. Also check your Tire pressure.. W/ the above mileage I get was with my tires being off by 1 - 2.5 psi, I will post if I get more after I fill up again...

 

If you guys are pinging on 87 octane you have a serious problem and need to take your car into a dealer.

Your PCM has two spark tables, one for high octane and one for low. If it detects low octane it automatically switches to that table.

 

True, but on that lower spark table you're getting less performance! It is recommended in the owners manual that you use 91 or better.

Definetly check those 02's.....then clean your MAF sensor...be careful doing it, I use alcohol and ear swabs to clean the metal wires in the MAF.

 

O2's can be bad and not send a light. Say they just read lean when your not, so the comp dumps more fuel in it. This would cause both poor gas mileage and poor performance. I say take it to the dealer and make them do a diagnostic on the O2's, you don't want to be stuck paying for those!!
Dan

 

Well i cant say how much I usually get because I'm still on my first tank of gas. But as it stands now, I have 1/4 of a tank left, and I've got 250.3 on the trip odometer. I reset it at the gas station when I filled it up. This is with a 2000 SS A4.

 

is there a way to check if o2's are bad with a scanner like autotap?.. i'm planning on buying that and i had a fren scan my car with another tool and he said everything was fine... i have not had a ses light at all... and yes o2's are $$$$.. so i really dont wanna spend for those..

 

The way I checked mine is this(on my mustang): Hook your car up to auto-tap and pull up the voltages being spit out by the O2 sensors. They should be changing by .5-1 volts (at least that’s the way it is on fords), if they jump around a lot (1v+) then it is probably bad, if they don’t jump around at all, then it is probably bad. Also, make sure that the two pre-cat O2’s agree with each other, if they are way off from each other then one is probably bad. The post cat O2 really doesn’t do anything but make sure you cat is working. You could also try going to autozone(or is it pepboys) and asking them if they will test your O2’s for free, I’m not sure of their policy on this, but I know they pull codes for free. Again, I am used to fords, so I don't know how accurate this is. Best of luck.
Dan

 

thnaks for the info.. ill give it a try when i get the autotap..

 

my 2000 z28 i go school which is 360 miles away from me and i make it with one full tank of gas crusing at 75 mph

 

Holy crap!
How often do you use it? How much mileage does it have?
That gas mileage you are getting is pretty good

 

most of you are lucky, i rarly see over 160 to a full tank with my set up, and I can never drive it normal for a full tank, its too tempting

 

also it depends on how u drive the car ...if i drive going to school with a heavy foot most of the time then no i won't make it with 1 full tank of gas, when i go i just use cruise control and relax and i make it there with one full tank of gas.