I try to take really good care of my 15 year old car so it really bothers me when I only get 16-18 MPG City

Hear is where I stand:

Just Cleaned EGR/TB/IACV
Clean Air Filter
Warm Idle of 650 RPM
1 year old Knock Sensor
1 year old Spark Plugs
2 year old O2 sensors
100% City Driving
I do not drive the car very hard because I’m not getting anywhere fast (auto shifting around 2500RPMs)
A/C is on 90% of the time (Central Florida)
No Vacume Leaks
checked Tire pressure a month ago

What am I missing? Or is 18 MPG good for city in the heat of summer?

Thanks for the input!

 

what sort of gas are you using in the car? If you're buying cheaper gas, you might consider trying some fo the better stuff to see if there's an effect.

Nice car, BTW.

 

EPA estimated mpg for AT is 21 city/28 highway.

Yurs is less than that but it is 15t yrs old and it an auto. AC on all the time will amount for some gas usage cuz the engine idles higher to run AC compressor.

What size tires u using? what grade gas? Last time u used chevron techron?

 

Check your tire pressure, stop using your AC.

 

A/C kills my mileage in the summer I only get like 14city

 

only 93 premium nothing but the best for my baby

 

I agree with the posts above: city driving kills the mileage in this car and the A/C will not help either. The suggestion about the tire pressure is a good tip also.

 

215/50/17 FYI

Found a problem tire presure was down to 27PSI in the front tires What should i shoot for 35 PSI?

 

Look under the lid of your center console and theres a sticker with the recommended pressure on there. I believe it's 33 front and 32 rear but I could have those backwards. I try to get somewhere close to those numbers when I check mine.

 

Definitely look in the console. I notice you have 17 inch wheels. I'm not positive about this, but I think that the pressures will be different due to the different shape of the tire (less sidewall).

Also, do you ever run fuel injector cleaner through your gas? Techron is supposed to be pretty good stuff.

 

So true so true....

 

I Pick up a bottle of fuel injector cleaner every few months when I see it on sale (@ Wal-Mart or Advanced auto) I don’t like using it a lot because I have heard that it fowls spark Plugs

I did put a bottle in yesterday to try to fix my problem FYI

 

I have a feeling it wont get much better than that. I would figure that having the A/C on 90% of the time is the reason, that and the city driving. Not to be a downer or anything :P

 

Try overinflating your tires by say 3 pounds, 36F, 35R.

What do you mean by city driving? Lots of lights & stop and go? What speed are you maintaining when the traffic is flowing?

 

I bet one of your rear calipers is seized.


One of mine was/is. Found out last week. one of the break pads was as thick as a cracker.

 

I see many saying this. Jacking the rear and turning by hand should be the best way to check right?

 

I will CHeck Tonight, I had thie problem one time with my mr2 so I know it is possible However i had the rear calipers rebuilt no more than a few years ago

THx

 

I've given up trying to figure why i get crappy mileage and just chalked it up to age. In the last 4 months I've changed plugs and fuel filter, cleaned the k/n air filter, changed both front o2 sensors even though no code was thrown, clearned the EGR tube, over-inflated the tires, cleaned the MAF, and even put in some fuel cleaner as a last resort.

No change whatsoever. I still get 17 to 18 miles per gallon of spirited mixed driving.

 

yo red man...im feeling the ride kid. nice work sir! YUP!

 

If you idle a lot, your mileage sounds pretty decent for city driving. Running A/C, our cars consume about 0.7-0.8 GPH at idle, and that's when they're running right. One thing I didn't see in your maintenance list is spark plugs. Might want to check those if you haven't changed them in a while.

Also, overinflating your tires will probably only help appreciably if you do a fair bit of highway driving. The kinetic energy that doesn't get absorbed by tire flex just goes into the brakes in most city driving scenarios. I really don't think you will notice a difference in mileage unless they are severely underinflated.

 

Thanks I try to do good work



My New Theory is that my fuel system is not sealed properly,

When I open the gas tank I should hear it depressurizing right?

I have checked everything else I think my next move is going to be a new gas cap and through check over of all gas lines

 

well how much stuff do u have in the trunk? if u got a lotta stuff the mpgs will go down too.

Jus as an aside, I did a lil mpg experiment w/ my car. Im gettin 27-28mpg highway with 93 octane. I was impressed.

REd, U change fuel filter?

 

For pure city driving with an AC, 18mpg is quite normal. Especially if you are heavy on the gas and like to rev up to and a little past 3k

And for highway cruising at a steady speed of say 55 mph 28mpg is quite normal.

I've done a lot of both. =)
Long trips to lakes or something like that 28-29mpg.
Going to work 4 days a week in city only - 18 mpg.

 

Just Spare Tire and Jumper Cables

I replaced the Fuel Filter about 10K ago

 

well if highway miles not off or is close to EPA, then not much u can do to get better miles.

 

funny... 1996 infiniti i30, the other day i used 8 gallons of 87 bargain no name gas station brand gas and went 132.2 miles. the following day i added three gallons of sunoc 89 octane and have so far gone 81.0 miles on it and its not quite at E.

math time:

s**ty gas got me roughly 16.525 mpg, given i had a 100 pound passenger with me for 50 highway miles

sunoco gas achieved exactly 27 mpg, with 30 miles on the highway with the same passenger and also more a/c use, which is honestly negligible on gas, IMO.

that poorer gas cost me 28 cents less per gallon, though... and it was used in some heavy traffic, about 5 miles over 40 minutes...

just my .02...

who else has some figures?

 

also, not to be a d***, but there is a typo in your sig

thought you should know

GRAMMAR POLICE
BOSTON UNIT

 

we had a flood in nashville back at the beginning of may. 3 hours of traffic, moved 5 miles, level 3 a/c. My car used about 1/4 tank. That was constant stop and go though, and it was over 90 outside, so the car probably was hot as ****.

 

ChrisMan287 - we in Florida have to run our air - or we get to where we are going SOAKED in sweat - it's HOT and HUMID here.
Yes, check tire pressure (as rated on sidewall) -

Nice car - couple of things to consider, heat evaps fuel - so we in Central Florida loose gas from this regularly. Check you cat... mine was clogged - I'll be testing my mileage with my next 2 fill ups.

 

Thanks, I just started having this problem two months ago when I moved to Orlando (From Tampa) I think my commute is killing me too it takes me 20 minutes to drive 4 miles a day

 

Yo man, if u puttin in that hat's off cheapo gas in there what u expect lol.

Da only cheap gas i put in my car in boston on gallivan blvd across from mcdonalds.

Sunoco is always good gas. Mobil is crap. Shell is the best.

 

Jeez you live 4 miles from your job - lucky you.... I drive about 28 miles each way to work. (thankfully I can run I-4 for most of it - and as I leave the house at 3:20 am there is no traffic)...

I was averaging about 21MPG before the catalytic converter issue ... I suspect that my heavy right foot/running the air is to blame, though like I said I'll be recalculating my mileage with the next to fill ups to see where it's at now.

 

Sheesh you guys expect too much from a 15 year old luxury car with a 6.

A/c never hurts my gas mileage, and always premium. I cannot believe that after 15 years people still put the crap in.

Maintnence is key, obviously if you have bad O2s or a bad knock sensor or MAF your going to get crap mileage.

 

So When I drove to Tampa this weekend (75 miles down I4) I got 19MPG with cruise control (65-70MPH) and some AC
Needless to say I was overwhelmed with joy when the it thru a code in Tampa this weekend
“Fuel Injection System lean or rich” – 0806 (left bank) & 0706 (Right Bank)
FSM Says Check:
Intake Air Leak (Plausible)
O2 sensors
Injectors
Exhaust Gas Leak
Incorrect Fuel Pressure (Plausible)
Mass Airflow Sensor (Plausible)
Lack of Fuel (Plausible)
After I reset the computer I got 27 MPG on I4 on the way home! However the code came back about 100 miles down the road

So what should I do about this code? Im leaning towards FPR or MAF as the problem

 

Clean your MAF first and check wiring harness. THen try everythin on your list. FPR would be last to check.

That code seems to originate from teh rear o2 sensor. Might just need to change that too.

 

18 MPG for Florida isnt all that bad...Thats about what I get. If i only Drive in the city (downtown Fort Myers) I get about 19-20.5 MPG, Mixed driving 20-24mpg, highway at 70mph no stop etc highest was 32mpg but average is about 26-30mpg

I believe thats with an exhaust leak as well

 

Checked the Fuel Pressure at idle was 35 PSI
I replaced the Rear O2 Sensor and cleaned the MAF
The problem persisted until I reset the computer, now it is running fine
now I am wondering if the CEL will come back

 

Nice, RedfoxXx!
I can also participate! My MPG is even less then yours It's 14-16 MPG in the city and around 20 MPG highway.
I've changed everything:
both O2 sensors,
knock sensor,
fuel filter,
spark plugs,
also installed a K&N filter in stock housing,
no errors in the system,
the tires are pumped with nitrogen.

What else to check?
May the clogged cat to make such a huge consumption?

 

use nitrogen in your tires, its a drier gas and holds the psi better w/o having to check all the time.

 

Ok, looks like 14-16 MPG is normal for the car