I was intalling the O2 housing, and of course destroyed the o2 sensor (it was almost melt in the o2 housing), I bought a Bosch universal sensor and splice it........the results are incredible; before I used to get 21/18 mpg (evo 9 MR) the car is still new with 8000 miles. so I doubt the sensor was bad, anyways just wanted to let you guys know if you are getting poor gas mileage it might be time for a O2 replacement.

 

interesting

 

What O2 housing did you install? I just got my Megan O2 installed last Tuesday. I'll definitely be watching my mpg on my next tank. That would be awesome if it improves.

 

I have the megan too, but I think you misunderstood me, the improvement in MPG came due to O2 sensor replacement, I doubt that a better O2 housing will affect your MPG.

 

i agree\....i have a evo8..with 32k...and im changing my o2 housing on monday...a new o2 sensor i bet will change the mpg..right now i get 225 to a tank...not even driving hard.....i bet the fuel map from the dealer is so wack..that if you do any mods it just pulls timing and dumps a lot of fuel...i went from a 108 mph trap speed to a 104...with a CEL and some warmer weather....im putting a ebay o2 housing..10.5 ported bucher hotside and a smc meth kit.. i will post results..
before hand ...317whp...327tq...
after >>>??????hopefully alot more

 

I'd bet the o2 housing is leaning you out a little= better gas mileage.

 

31mpg is an evo? yeah right. thats impossible. my beater 00 civic automatic barely even gets that and most of the time gets 28-32mpg
i have always log my mpg and have talk to many evo owners and the evo is definately a sub 20mpg car.
my life time average is 17mpg. if i do a lot of freeway with little to no boosting i can get 19mpg. my record for is 23mpg and thats with one long freeway trip with no stoping.

 

I'd be interested to know how much AFR changed...

 

rice ball have u ever had a reflash.....my car was the same way ..i got a relfash and gained about 30 to 40 miles to my tank

 

You must have a big, heavy foot. I have never done worse than 20mpg. If I stay out of the boost 31-33 hiway is easy. Well, not so easy. Damn boring driving that slow!

 

My car's mpg didn't increase after my reflash, overall I pretty much always get 19mpg with a mix of city, highway, and "spirited" driving.

 

I have had 25mpg on nthe freeway and that was cruising at 80mph. I also had an AFC at the time and I am sure a flash will net better mpg.

 

i still get **** poor gas mileage after flash

 

To get 30mpg you must be driving all hyway and going like 55mph(IMHO I don't believe it)...I average 19mpg, I once got 21, and lowest 17mpg.

 

I just averaged 27 mpg going to Wisconsin, and that's bone stock. I did bump up my tire presssure to 38psi, and I think that made a big difference.