so ive made 2 big road trips since i got my max few weeks back.

190k+ miles now. with a bad knock sensor.

1st trip:
round trip to boston from nyc. 24mpg, and 26.3 mpg coming back
avg spd was 72-75

2nd trip:
nyc to toronto. going up w/ 2 fillups. 27.x mpg and a miserly 23.x mpg.
average speed 80+
coming back 27.x mpg on 1 full tank.
average speed 80+.

not bad for such an hi mileage car.

 

Not bad, my guess is that you keep up with maintaince?

 

I think he said he did it with a bad knock sensor. If thats the case he had changed the knock sensor he would've squeezed out at least 30 to 32 mpg

 

Isn't it the o2 sensor that can cause poor fuel economy?

If the knock sensor could affect fuel economy, that would be like saying super yields better mileage than regular, which we all know to be false. I would say logically that with a bad knock sensor, the motor cannot detect knocking, therefore it cannot retard timing normally. If designed properly, it would then automatically retard timing to protect against knocking, and in such a case, it cannot benefit from 91 or higher octane. But what do I know...

 

Another gas mileage thread.....

 

I didn't know that the knock sensor affect gas mileage.

 

knock sensor makes your car go into limp mode. Limp mode is design to protect your car from doing any harm when something goes wrong. It gives you a lot less power, less power would mean you would step on the gas a lot more the normal therefore causing you to use more gas, and the final result bad gas mileage and less power


maybe i'm wrong but my idea of how the knock sensor works =P

o2's measures amount of air flow at the headers to adjust for amount of fuel used in the combustion chamber.

 

Good theory, never thought of that.