MPG problem

[Lil' Shaun]

I'm getting about 10mpg
I keep getting a code that comes and goes for fuel trim bank 1
the light usaly comes on when cruising at 2200rpm
I just checked the plugs 1&3 are lean 2 is good and 4 is rich
I have even compression and no boost leaks and nearly no mods.

 

[rich3389]

Most likely needs a new O2 sensor.

 

[Lil' Shaun]

how would that make it rich and lean from one cylinder to the next?
Oh, i for got to say its on a 2G GSX

 

[luv2rallye]

Which error code are you getting? If P0170 there's 9 things it could be.

 

[Lil' Shaun]

if it comes back on today on the way to work I will look at again. I didnt even look at the number I just rear what it said.

the code is P0170

 

[luv2rallye]

P0170 is usually caused by O2 sensor but it can also be due to volume air flow sensor, injector, fuel pressure, intake air leaks, ECT sensor, intake air temp sensor, barometric pressure sensor, exhaust manifold cracks, incorrect fuel used, ECU failure.

 

[ramsack]

when was the last time you changed your fuel filter? seeing as how the cylinders are seeming not evenly fueled, that's the first thing i would check. if the filter is blocking fuel a bit then cylinder 1 would get the least amount of fuel.

 

[98GSXin]

Is it only a recent issue or has it been like that for a while? Are there fuel system/ turbo mods that are sucking more?