2002 blue z28

iTrader: (1)

I know there are dozens of threads talking about bad gas mileage after a header install, and how a tune is supposed to fix it. But, I was talking with the guy tuning my and he told me there was no way to fix the issue through tuning. So, is there a way to bring my gas mileage back up to a somewhat decent amount? As is sits right now i'm getting around 10 MPG in town. Any help would be appreciated.

Latch

iTrader: (8)

If you're getting 10 mpg there's something wrong besides the tune. I am getting the same mileage as stock if not slightly better after my header install, and I have not had it tuned yet. If I had to guess I would say your car is not going into closed loop, what did you do for 02 sensors?

2002 blue z28

iTrader: (1)

I reused the stock ones.

2002 blue z28

iTrader: (1)

The tuner says there was a delay on the front o2's. I figured it was because they're alot farther down than they were on the stock manifolds.

Latch

iTrader: (8)

Did you make extentions or repin your PCM?

2002 blue z28

iTrader: (1)

I never messed with the PCM and i used the o2 extensions that came with the headers

Latch

iTrader: (8)

02 sensors are very sensitive to shock, were they dropped at any point during the install?

2002 blue z28

iTrader: (1)

I never directly dropped them. When I was taking out the stock manifold and cats I kept the sensors in the pipes and just disconnected them where the wires clip in. They may have experienced some shock, not sure.

Latch

iTrader: (8)

Does the car drive fine, no misfires, feel fast? If you haven't done so already, check to see if it's throwing any codes besides the ones it should be throwing due to the missing emissions equipment.

2002 blue z28

iTrader: (1)

car drives great, no misfires. I got it scanned a few days after the install and the only thing that popped up was the rear o2's. Is it possible that a new intake manifold could be causing this?