For the first 18 months I owned my 2000 5 speed Maxima I always got 29-30 MPG. Now I’m struggling to get 25 MPG. I’m driving the same and using the same gas. I always check the tire pressure and keep the air filter clean. Does anyone have any idea why this is happening?

 

If you live in a cold area, additives are added to the gasoline which may reduce the mileage. Also, if its colder out, the car takes longer to warm up, and runs richer (i.e. burns more fuel, especially on short trips). I've noticed here in CT that I get about 19mpg, where I used to get 21-22mpg in the summer. This is of course doing mpg on a calculator, and not relying on the trip computer.

 

Yesterday I calculated mine MPG and it was terrible. 14.7 mpg!!!
I live in chicago area.

 

Don't rely on the trip computer. You weren't getting 29-30 mpg. Probably closer to 25-27.

 

2000's didn't have trip computers.

 

I would also attribute the falling mileage to the cold temperatures. You mentioned that for the past 18 months it was "fine", so this means you already had a winter with the Max, and yet mileage stayed in that range. So, was the first winter mild compared to the current one?

I would wait until spring, and see if it goes back up, and if so, you'll know the culprit.

 

Hmm. Learn somethin new every day. . .

 

 

i've been averaging 12-16 ever since this COLD A$$ winter started.
dont' worry, you're not alone. this also includes my majority of driving in stop and go manhattan traffic.

 

Good to hear that,that I'm not alone .I hope that will be better in the summer.

 

Well, thanks everyone for the suggestions. I suppose it could be the cold temperatures. This is the first really cold winter (I live in PA) I've had to endure since I got my Maxima. And yes, in the past, I really did average 29 mpg. I almost always check it when I fill up. Most of my driving is a slow steady 45-50 mph with some traffic lights, school buses, etc. mixed in.

 

Hey man, you might not want to hear this....
I had the same problem on my 2001 5 speed. It became really difficult to hit 25 mpg, and 23-24 became more of the norm, even w/ highway driving. The tranny shifted notchy as all h*ll too.
Have you ever changed your gear oil? I changed mine off of the factory fill @ 52,000 miles. To my dismay, what drained out was gold flake soup (very fine particles, and alot of them in my gear oil). I haven't sent a sample out, but if you look do a search for threads, you'll find a raging debate about 5th gen synchros and the problems people are having w/ them.
Anyway, to make a long story short, I changed gear oil, and presto - 28.5 mpg on the first tank. I've been keeping track since then, and I haven't fallen under 26.5 mpg in the last 1,200 miles, even in 20 degree weather. I'm not saying that's the source of your problem, or that changing the gear oil will fix it, but it's something to consider.

 

Hi everybody
Just thought I would put my two cents in. I cant believe my maximas terrible gas mileage. Its only a 3.0 Litre at 15 miles to the gallon on premium fuel, if im lucky! 1995 Cobra SVT 5.0 Litre 20 miles to the gallon low test fuel, winter or summer. There is something wrong with this picture.

 

I have a 03 AT. I am getting 16 MPG with the recent cold temperature in the Midwest. 25MPG is pretty good