I got a 03 Maxima w/ 105,000 k on it.
I am getting horrible gas milage.
With a full tank of gas I'm getting only 190 miles with my maxima.
It has been getting worst and worst.
What can i do to find the problem?
There is no engine light on, and the car starts up fine!
What are some things that need to be changed or need to be cleaned out.

Thanks for the help

 

try some of these. oil change, filter wash, seafoam, o2 sensors, tire pressure, alignment, maybe the maf sensor, change spark plugs.

 

Are you actually checking your mileage? Fill it up, drive as you typically do, refill and divide the gallons used into the miles driven. Our trip computers are notoriously inaccurate with respects to gas mileage so make sure you actually have a problem first.

If your car drives fine, has good power, no SES lights then I'd first focus on your driving style. Do you take a lot of short trips? Bumper to bumper traffic? Live in a city where you have to stop at every light? Accelerate hard when you leave a light? Regularly drive well above the speed limit? You don't have to drive like an old lady but keeping your foot out of it will definitely help.

Mechanically, first things I'd check are the air filter and tire pressure. You'd be suprised at how much those two items can affect mileage.

 

Another cause of really bad MPG is a dragging brake or bad wheel bearing. The easiest way to check for a dragging brake/bad wheel bearing is to jack up the car turn the wheel by hand.

 

QFT. I find it hillarious when I return from a trip and my dte is higher than when I left.

 

stop the speed racing?

 

Last road trip I took, I was regularly getting 30+ mpg (best was 31.4) showing on my trip computer keeping my speeds between about 72-77, with a few quick passes around semis but doing the actual math gave me a lowest of 25.8 mpg (which was the leg of the trip I hit a driveshaft laying in the middle of the highway in Arkansas and blew a hole in my rim) to a best of 27.4 mpg.

In town (maybe 20% freeway thrown in), my trip computer shows 21.5-23.5 and my actual mileage is 19-20.5 or so. Worst tank I ever got was during the winter with a bad thermostat and that was 17.5, mostly city driving.

 

Do you keep it seviced regularly? If not,go for a tune up...

 

The following three things helped my 03 Max to increase from 350 miles per tankful to 400 miles per tankful.

- Replaced air filter, the old one was really dirty
- Changed the oil
- Increase the tire pressure from 25 to 33-35 PSI