just finished doing the maintenance on it and it is still getting crappy gas mileage.

car has 134k miles original everything
auto tranny stock size wheels

replaced new:
radiator and all hoses
new honda thermostat
new coolant
new oil and tranny fluid
new cap rotor wires and spark plugs
both O2 sensors are functioning properly

timing is set to OEM specs
compression is 180 all 4 cylinders

no oil or coolant leaks
engine runs very good and accelerates good also
car is completely stock
no codes
no drag on brakes
i used heat rating 6 plugs with smaller gap as was suggested in one of the threads here to make up for added ethanol in gas. but it didnt change anything


is there something that im missing here?

whats the typical gas mileage of auto LS anyway?

 

Dirty air filter?

 

Didnt look like but i guess i might as well replace it.

 

Fuel filter? Have you tried seafoaming.

 

fuel and air filters

your o2 is highly suspect. all it takes is a small change in voltage to make the car run really rich. normally this will trigger a CEL. a plugged cat can also kill mpg

 

check the ect sensor resistance. first cold, then hot. see if it falls within spec

also, may sound silly, but check your tire pressure.

 

tires are good.
new fuel filter( forgot to add) i did do seafoam as well. and the engine has alost zero sludge its golden like it supposed to be

only thing i didnt do is check valve clearance.



well heres both O2 sensor readings looked normal to me

 

My 2000 LS w/auto gets 29 mpg city and 34 hwy. It has 106xxx miles on it.

Last year my mileage dropped, when my cat went bad, but I did not get a check engine light. I ran with a test pipe for a couple weeks and my mpg went back up.

I bought a used OEM cat and installed it. I am back to my normal mpg 29 - 34.

 

looks good to me too, i'm with safe for your next task. the B series in general tends to run rich and burn anywhere from a little oil to a lot of oil. years back i pulled a melted one off a stock gsr with 150k miles.

might be worth pulling yours for the sunshine test {aiming cat at sun and looking through it}