i have a 98 max with a JWT POP intake and Budget Y-pipe on for about 4-5 years now. i have around 120k miles and my mileage suddenly got real bad..like hummer mpg. MY exhaust smells like gas when i start my car also.

What could be the reason for this? time to change intake? faulty 02?

any input appreciated

 

ever replace the KS?

 

What would the intake have to do with it lol

But it could be your KS you need to pull your codes off your ECU or take it to autozone and let them

 

Lets start at the benining.

Whats your actual MPG?
Full tank consumption - #gallons used on the pump/miles driven.

Post those results, then lets talk about it.

 

How much do you lose (MPG wise) with a bad knock sensor??

 

I was told you lose 2 mpg.

 

There are so many variables here, it's foolish to start throwing things out like "Must be knock sensor!!!"

If you're smelling gas, is it leaking?
How many miles are on the car?
Have you pulled any codes from the ECU?
What color is the exhaust, if any?
What color are the spark plugs (check all 6)?
How many miles since the spark pulgs were replaced?
How many miles since your last fuel filter change?
How many miles since your last air filter change?
Have you ever replaced the knock sensor?
Is your tire pressure correct?
Is your alingment correct?
Have your driving habits or traffic patterns changed?
Is the type of fuel you've been using changed (both by Octane rating or by gas station, since some use different winter blends)?
Have you done any recent mods to the car?

Most importantly, SEARCH before you POST. There must be 10 threads a week on fuel economy.

 

What mpg are you getting? You never stated that.

 

Inflate your tires....

 

i never really measured, buts apprx half of normal. i was told the 02 sensor might have anything to do with it?

 

Take your foot out of the gas, that usually solves my mileage problems

 

well how about before we go guessing everything that could be wrong you check what your actual MPG is, see if your check engine light is on etc etc. Have to put a little work in before anyone can even guess what is wrong. Otherwise you will end up hearing just about every sensor imaginable as almost anything failing on your car will probably effect your mpg in some way. Take a look at the nice checklist above and then get back to us.

 

my moms i30 gets 23mpg. 370 miles and 16 gallons on a fill up. plus her knock sensor is throwing a code

 

my maxima can get about 300miles, but I have an acceleration problem, I love the power

 

power is cute.

 

300 miles to a tank is fabulous.

 

power is cute.

 

300 miles to a tank is fabulous.

 

Power is cute

 

300 miles to a tank is fabulous.

 

power is cute.

 

300 miles to a tank is fabulous.

 

Gas mileage is overrated

 

Gas mileage is overrated

 

Dipsticks are underrated.

 

WTF is up with all the avis????

 

Dipsticks are fabulous.

But seriously try http://forums.maxima.org/showthread.php?t=72447&page=2

Post number 38 talks about causes of low gas mileage, try there first.

 

Try changing your air filter, inflating tires more, and change 02s with new Denso ones. Taking these easy steps would easily increase your gas mileage.

 

I would check to see if your ECU is throwing any 02 sensor codes, then try to see if they need to be replaced.

 

you are running rich probably. check o2 sensors.

 

You are running rich and fabulous.

 

 

YOU ARE running rich and fabulous.

 

Dependent upon just how rich you're running, I can help out.

 

If your engine is running rich, This might be a sign of 02 replacement or even MAP sensor replacement....I think it helps to regulate fuel management....I would aslo try cleaning your TB and EGR and just get all the carbon build up and other gunk out.

 

i am only getting about 200 miles out of my i30. I konw one of my 02 sensors is dead but what else would cause this extreme loss?

 

Well i just filled up today. I did 225mi on 16.23 galons , which comes out to 14 some MPG. This is unacceptable...i am going to get some work done on it...including

-alignment
-balance
-oil change
-o2 sensor testing

 

You are running rich. You should check your engine.

 

can the MAP and o2 sensor be self replaced? i should check the faq's right?

 

Here's the O2 How-to:
http://forums.maxima.org/showpost.ph...2&postcount=24

How much would be a reasonable price to have a shop test and/or replace the O2 sensor?

Or maybe the better question is: How many hours should a shop bill for those services?