I traveled 60miles half city and half highway and used a little over a quarter tank of gas.. i only redlined it once after a toll... I cruised around 70-80mph.. am i running rich with this new header? cuz i feel like my gas mileage has gone down...

 

reset your ECU by disconnecting your battery terminal.......

 

have you documented your mileage to see what you are actually getting?

 

You'll not use so much gas if you keep your rpms down :o

Cruising at 80mph is not the way. Keep it to 65/70 and you'll see an increase. City driving with stoplights and traffic isn't good either. It's not your header, it's your driving habits.

 

my driving habit would be shifting 2500rpms regularly or redlining like crazy.. overall, i guess i'll just reset the ecu, but i hope my CEL won't go on... i've been over 2000miles CEL free

 

It'll go on, I went 200miles before it came on. I'm surpised it didn't come on yet. Did you damage the O2 sensor when installing? If you didn't reset the ECU after install that could be the reason.

 

no i didnt damage the 02 sensor.. i just gota stop redlining...

 

check and make sure the headers are tight enough... if there isnt an airtight seal, it may mess with the O2 guage.

 

So your gas mileage should not change when you put on headers?

 

it should get slightly better because its better flowing. my mpg got better. ive seen 33 mpg on some trips

 

most cases of running too rich is because of the O2 Sensor having incorrect readings. A cel light will not tell you that 100% of the time. But easy fix is a CEL Eliminator which will put your O2 readings back to normal.

 

i heard a header can decrease gas mileage by a little bit, because of more combustion caused by a more free flowing header...