My gas mileage has gone from 380+ miles a tank of gas to 310-320 miles a tank of gas.. anyone have any suggestions.. About 3 weeks ago my CEL was on.. after replacing the ignition coil it went off.. Ordered the part from Dave B, we had a slight miscommunication, where I have a 99 max, and he sent the part for an 00 max. I had a real important business trip I had to get to that weekend, so I just popped the 00 coil in, and the light came off and stayed off.. Called Dave B, he said there is no difference in the coils, except there were two screws to hold it in place on the 99 and one for the 00.. Think this could be the problem? Also, when I floor it, almost redlining it, there is this real high pitched buzz that comes from the engine bay until it switches gears..

Thanks for any help!

ECK

 

Could be too many things for me to just take a stab in the dark...

Winter fuel?

 

Since the tank holds 18.5, you're saying your mileage dropped 3.75 mpg. That's a gray area, imho you need to get a better handle and find your actual mpg, not say you're getting 60-70 less mpg per tank. I drive the bump-bump daily and avg 22 overall. Sometimes I check it and it comes out 18.5--one serious traffic jam in a 5-day commute could easily cause that, I wouldn't conclude something is wrong with my car.

About your coil, I don't think it would cause a problem. But if it were me, I prefer to have the correct part. Somebody did that to me with the front brake pads, told me the Altima pads are the same as Maxima even though the part# was diff. I said whoa, just get me the right one. Being the honest person that I am, I have to admit when you hold up the pads to one another, they were identical to the eye. But again, I prefer the correct part so the dude told me just keep both sets, no biggie. Shows you how much markup there is in Nissan parts, he discounted it 30% with free shipping and let me keep 2 sets for the $44 I paid.

 

List your mods...

Also, check tire pressures, run some good fuel injector cleaner through your system, and do not rely on your trip computer to figure the MPG for you.

 

If he can't rely on the car to tell him gas mileage what can he rely on? The trip meter is there for a reason.

 

here is a list of items that may give you better gas milage, i believe more detail informations are in the 4th gen sticky:

mechenical part:
1. check tire pressure
2. clean throttle body
3. clean air filter
4. check spark plugs
5. clean IAC valve
6. check engine coolant temperature
7. clean knock sensor

also use 91+ octane, and don't shift too hard. (i.e. shift_3,000rpm).

 

Yo, not everybody knows how to take km traveled and divide it by liters consumed, and convert it to mpg's. If that were the case we wouldn't have pc's with MS Excel. You teach everybody on the forum to add, subtract, divide, that'd be money. G-money.

 

wait, the max 4th gen has a 18.5 gallon tank? If so, my mileage sucks even worse. I got about 320 last tank. and that's a pretty light foot.

 

I've never seen 3xx miles on my trip odometer I think I might make it to 3xx this fillup since this time, about 50 miles were highway miles

 

well ever since i put my new front right 02 sensor in i havent seen the almost out of gas light and i change gas the same time, right in the middle to lower end of last dash of gas meter. My last refill i put in 16.7 tanks of gas (forgot mileage). I am happy to see i had lots of driving left

 

When the gas light comes on, I usually have 3 gallons of gas left in my tank! When i fill my tank, i usually put in about 15.2-15.6 gallons of gas when the light has just come on. Thats nuts, b/c i could get another 60 miles out of that! i usually get about 360 m per tank
but lately its been 300, maybe less. I need oil change and plugs!

 

WTF are you talking about dude?

 

I've got a 3rd gen, but I get about 300 miles to a tank, w/mostly city driving... I can get a good 150-200 out of a quarter of a tank on the highway...
And my gas light never goes on... ::shrug::

 

I fill up with 17.5-18 gallons. I only get 17.6 MPG because i do all city driving.

 

140 per 1/4 tank is conceivable (he said 150-200). There is a stretch of I-87 S from the Canadian border upon which I have sustained 32 mpg, well, when the car was about 1-2 yrs. old. It really has to do with how much hills etc. there are. Best I have done in the last 3 years is 28.5 mpg though.

 

Well when I'm not using my heavy foot I can get up to about 330-350. That's with an occasional get on it and go moment to 4,500 to 5K. And that is with all city driving.

When I'm on it only about 220-250

141K on the '95. Needs it's oil changed badly. I wouldn't be surprised if the spark plugs need to be changed, I don't know when my dad had the car last serviced.

I have already cleaned the Throttle Body, and checked the tire pressure, I think I'll do those other things and see what will happen.

Last time I checked my mpg I was at 24.9 so 25 MPG. I have an intake, and use 93 octane. Not bad at all IMHO.

 

I don't think so either. I'm just saying that's what I've observed... Last weekend, when I came back to school from Turkey Day Weekend, I filled up before I left home, and when I got to school (about 85% highway driving on cruise), my gas gauge was down a little below half, and I was on about 150 on the trip odometer.
I'm not sure why I put the 200 - I was thinking about another long trip I had recently, and that was 200 miles on half a tank... That seems more realistic.

In any case, I don't think my gauge works right anyways, as my gas light never comes on, even when I'm directly on E...

 

When I'm on E, I have ~3 gallons left. When the tank has ~2 gallons left, the light comes on.

 

Aah, I see...so I really don't hafta worry about it until the light comes on eh?
The intricacies of "new" cars...

 

Maybe your light is dead