confused

[ser456123]

Hi
I have a 05 Toyota Sienna v6
Initial results after hydrogen install gained 10mpg over stock.
After about 70 miles ecu started to richen fuel mix bringing mpg to 16 which is worse than stock usually 18mpg.
This vehicle has a maf ,map,2 afr and 2 o2 sensors.
What do i need to add to counteract my ecu.

Thanks

[ser456123]

Please help anybody

[Painless]

There are others on this forum better equipped than I to answer this question, but I would suggest starting with some O2 sensor extenders and moving on from there. You can make these yourself by buying spark plug anti-foulers and drilling out the hole to the required size. These will pull your O2 sensors out of the exhaust some and reduce the amount of O2 being reported to the ECU.

Once installed, don't forget to remove the positive terminal from your battery for 15 mins so that the ECU will reset.

If this doesn't work, then you will need to look at other electronics.

[ser456123]

According to toyota the o2 sensors are down stream one before the cat and one after the cat the afr's are on the upper side of the manifold.
Will a maf/map enhancer work with this vehicle?
Does anyone know?

Thanks