While driving around the past few days i've noticed a dramatic increase in gas milage. I just replaced my knock sensor and installed a cat-back but it just doesn't seem like those 2 things would cause a big difference in gas milage. On top of that i've been pulling the 0302 egr code but I do mostly city driving so I don't think that really has an effect on it. I reset the ecu and that code has not come back yet. I drive my car pretty hard and haven't always been getting the greatest gas milage but I haven't changed my driving habits and I can definately notice a gas milage increase. Usually I would eat up around 1/8th of a tank in 2 days going to and from school but now it seems like it eats up almost half that in the same trip. I'm guessing it's probably because of the knock sensor. I don't think a cat-back would cause an increase like what i'm seeing. Anyone else notice an increase in milage from a KS replacement?

 

people have stated that changing the ks makes the care feel different both in gas mileage and performance

 

KS will make a big difference.

 

Maybe a combination of the both? Nah the exhaust will probably make little to none increases in gas.

 

most likely the KS

 

also with the season changing to winter. gas companies have up the quality of gas. well theirs some additive to make it combust better.

 

how much was the Knock Sensor and where did you buy it? any place cheaper then paying retail from Dealer?

 

Actually they add more stuff so the gas won't freeze and that makes the gas mileage WORSE. Sorry to burst your

 

ive just always heard that some where. maybe it just combusts better due to the cold air associated with the winter climate. that also my cause and increase in MPG but not sure.

 

doesn't cold weather = denser air? that might improve the combustion too, won't it?

 

I know this post is not related to this thread, but I am not allowed to create new posts yet...

How do I know what type of VQ engine I have?
For example, VQ30DE or VQ35DE, etc.?
I have a 1996 Maxima...

 

You have a VQ30DE. The VQ35DE, denotes a 3.5 litre engine, introduced in the 2002 model year. You have a 3.0 litre engine.

 

I got the KS from ebay for $64 shipped. I also heard that they oxidize the gas in the winter and that it decreases gas milage and performance. But either way I don't think thats the cause in my case since i'm still living in FL.

 

Definately the KS, it makes a huge difference...

 

You can also tell by looking at the silver plate that's mounted on your firewall under the hood.

 

u cant base it off your tank needle. Yea maybe nothing has changed physiclly. drive same roads, same time. park same places and junk like that but the best way to define MPG is thru milage driven/ gallons. That way you can say. Hey i got 3 mpg increase due to KS and exhaust.

I just changed my KS and honeslty i'm getting worst mpg because i'm mashing the pedal more....=P i was already getting decent 20city-25 highway, specs for any auto isn't too far off i think 22/28. maybe my knock did help me but i wont find out this tank of gas.

 

Or check the block where the KS is located.

 

Unless you put on 1000miles in the last few days, I don't think you have an accurate statistic. I need to average about 3-4 tanks to get a good reading since each tankful will vary. So if you have a really high mpg the next tank will calculate lower, and the values always yoyo around like that. I think it's simply because the fill shut-off switch at the pump isn't consistent from one fill to the next.

So after collecting a little more data, you'll have a more accurate idea of the effect of the knock sensor.

Dave

 

The additives in winter fuel formulations are to make the fuel combust more cleanly and produce fewer emissions, especially on a cold startup. They're really only for cars without O2 sensors and cars that aren't functioning normally. They definitely reduce gas mileage for the rest of us.

 

i always thought Replacing the o2 sensors would get better gas mileage?

 

If they are defective, they replace your lost mileage.

 

If your O2 sensors are dead or dying, then yes, replacing them will give you better gas mileage.


EDIT: Damn, beat to the punch.