I'm using 91 octane, with a new KS, driving pretty conservitavely, 60/40 highway/city driving, with 150,000 miles. anyone know why I keep getting such low mpg? This is a far cry from the 25-30 mpg I hear about people getting.

you've got 150K that's y. A car with a lot of miles...

I have about 140k on a 97 and i get about the same amount of mpg. 21-23mpg

I get close to 28 only on road trips... my normal driving, (80% highway) but with constant acceleration/deceleration in traffic actually only gets me 23mpg (averaged across many many months)... when I do city only, my MPG is even lower - more like 21-22...

I have new O2 sensors, always use premium gas... and no trouble codes set... and its been this way for the past 60k for me...

Having a lead foot really hurts MPG too!! but its too much fun not to enjoy the power of the VQ engine...

I get 300 miles per TANK!

That averages to 300/16=18.75 MPG.
That really sux. I do have a lead foot though.

I think we have 16 gallons in our tanks.

oTranscendental - thats not a good way to measure mileage... the best way is to fill up the tank, reset the trip meter, drive around, at the next fill-up, fill-up the tank, and see how many miles you drove between fill-ups - then you MPG is (miles drive/gas added at fillup)....

E.g. Lets say I fillup, reset my trip meter, drive around for a few days and then fill-up again... lets say I drove 200 miles, and when I filled up the second time, I needed 10 gallons to get to a full tank, then my mileage would be 200/10 = 20mpg.

18.5 gal i believe

21-23 mpg really isnt bad at all, especially with almost half of your driving in the city.

do you have a lead foot?

you might try changing your fuel filter?

150,000 miles? If the 02 sensor is the original one. Consider changing it. Bad mileage is a sign of of one getting lazy. There might be an ecu test to see if it's cycling rich/lean fast enough. Check the faqs/stickys. A lazy 02 won't trigger a CEL either.
Also consider the fuel filter(as mentioned), plugs, PCV valve and EGR.
But IMHO it most closely looks like an 02.

Have you done the other general maintenance? Plugs, fuel filter? What else guys?

I'm guessing O2 sensor too....
But also check your tire pressure. I've read that about 5 psi off can reduce your gas mileage by 10%!

Use some SeaFoam to get some/most of the carbon out of your engine Clean your TB and other maintainance stuff (look at the How To thread).

I need new O2s since I'm getting like 16 MPG, but my car got hit yesterday so I have to get that straightened out first New O2s and an aftermarket y-pipe will get my MPG in the 20s

Has anyone who replaced their O2 sensors had a really noticeable improvement? I get about 21 mpg with my 97 SE, 100000 mi and original O2 sensors. With gas at its current level, the price of a couple of sensors that would save me in the long run looks pretty appealing.

I just replaced my 02's and went from 26 hiway to 30 hiway. The sensors only had about 35k miles on them and were done by the dealer last time.
Before I replaced them I ran a full tank of gas with Seafoam added to clean out all the crap and not get it in the new sensors.
I've also put Seafoam in the oil and my sticky valve is gone.
My Max has 147k on it and I'm telling you mileage doesn't matter unless the car has been abused.

Oh yeah, I'm also running my tires at maximum pressure.

i get 17 :0 Y-pipe+heavy foot. If im not getting any codes, could my O2 sensors or knock sensor still be bad, or starting to become faulty?

I can't stress enough how great this works. Take out your spark plugs and pour in a couple of spoons of ATF into each hole. Make sure the car is outside, put everything back together and enjoy the smoke show.

I drive mainly in heavy NYC traffic and get about 16-17mpg, i figured it was lead foot and lotsa traffic. Did any NYC members really see a difference in mileage after changing O2's and which one(s) did u change and how much did it cost. I have no codes and money is VERY tight so dont want to waste money if I dont have to. Recomendations would be great.

-carlos
im croman814
email croman814@netscape.net

You really can't expect to get more than about 21mpg in combined driving with an automatic. The autos do pretty good on highway, but around town their MPGs plummet. People that say they get around 25-26mpg in combined driving must either drive 20mph, only drive downhill, or they don't calculate their MPGs the correct way. I vote for the latter. My 5 speed SE which is in excellent shape (107K miles), gets about 21-22mpg overall (70 city/30 highway) with slightly larger rims and this MPG has been consistent for the past 5 years. In straight highway driving it gets about 27-28mpg.


Dave