I have been getting terrible mileage recently. Less that 10mpg in city driving. I took the PIDs value when the car was warmed up and stationary. Is there a list where I can compare these values to what should be optimal? Or maybe someone here sees something that is off.

 

What year is the car, how many miles on it, have you switched plugs, air filter, fuel filter or anything of that sort, and how long have you had the car for and was gas mileage always this ****ty, and how does the performance of the car feel....

 

Everything looks great in the scan (well, except the extra two banks of cylinders!)

Check dragging brakes and/or air pressure in the tire. All the OBD parameters
are looking very normal.

That is very good scan software! Can you provide more details on it?

 

The car is a 2001 AE SE with 147000 miles.
It has new ngk plugs air filter is about a year old. Mileage was about 15 previously.
I have all kinds of squeaks, creaks, and rattles from the front from old age. but I have had that for a while.
I thought my axle was bad because I was hearing like a train on the left side when I turned right but then it stopped making the noise and my mechanic checked it and could not find anything wrong. He also checked for play in the wheels to see if the bearings are good ( I was hearing a noise on my right that sounded like the description on this forum of a bad bearing) and he said there is no play.

The software is PCMScan and the cable I got on amazon with obd wiz

I first tried a cable from ebay but it seems the chip is a fake and it did not work.

 

Do my oxygen sensor reading look within proper range?

 

Go here:

http://boredmder.com/FSMs/Nissan/Maxima/

Download the ECM section for your year. There are oxygen sensor voltage ranges.

Other things to check could be clogged cats or fuel filter/screen. Nissan says lifetime on the fuel filter, but that is BS...most people on here have changed their fuel filter and see a difference before and after, including myself. Granted, I doubt you will see the MPG return to normal after changing it, but it will help.

FYI...only the primary O2 sensors (in front of cats) affect your MPG.

 

Clean/Replace the MAFS? Just did mine and it's a world of difference

 

The MAF is a new (about 8 months old ) OEM. Was working fine with no effect on mileage. I doubt it is bad

 

I noticed no diff whatsoever after I replaced my fuel filter at 90K in acceleration and fuel economy, and I feel manufacturers have a good reason for not recommending it. It's added value and peace of mind though if you do replace it every 60K though.

I'm guessing you've checked the obvious: tire pressure, make sure calipers and parking brake aren't dragging, minimal junk in the trunk, and you're not idling at drive-thrus for coffees or picking up friends/family or idling while chatting with neighbours? In cold weather, the engine runs richer when cold-started. My fuel economy goes to hell in this cold east coast weather (and fuel economy has been getting worse with age as I have 144K miles on mine.

 

I would difinitely check the pre cats and main cat to see if any or clogged I used to get real sh1tty gas mileage like 205-210 to a tank, but did New Plugs and Fuel Filter, deleted the Precats with the Cattman Headers big Improvement for the free flowing, tossed on the 3'' Exhaust also, and doing the TC-W3 thing, now I get about 245 or more a Tank.....

Here is a the thread for the Additive
http://forums.maxima.org/general-max...troke-oil.html

 

245 miles to a tank? That's a good thing?? I get closer to 390. What is wrong with your cars?

 

Not everyone drives on the highway.

 

Fair enough, I do about half my driving on the highway. I would figure even all city driving would net you at least 300 miles to a tank though.

 

I get solid 19MPG purely city driving on my 04 6 speed and i don't drive like a granny. It all depends how you maintain your car and what octane fuel you use. I could get more MPG if i timing advance but i cant find anyone in my area that can do it and the dealer wants $120 which is lol.

 

I've had my timing advanced for over 7.5 years and nearly 80K miles and have not noticed any improvement in mileage. Please provide proof before stating such.

 

I use the additive. Have not seen any noticeable difference.