decrease gas milage?
 

Kk so before i started doing a few mods i was losing about 50miles per tank... found out my resonator box for the intake was broke, so i put in a sri, and i do not romp it hard...
I did a tune up after that.. distrib/rotor wires/plugs.. still nothing. Been using premium to keep myself where i was before at about 300m a tank. Used to get 350.

I do know that winter fuel is cheaper then summer fuel and u will lose miles there, but im on premium and not back to normal. What is left to check? O2 sensors? Not throwing any codes... nvr had and the light isnt burnt out. Just made a custom straight pipe to muffler catback and would assume id gain a few miles back but hasnt been long enough yet.

98 accord 4cyl ulev sedan. Tires are fine..pumped to 35psi.. also brand new on front and good on back.

Any other suggestions are welcomed, tkx

Your intake can hurt fuel economy as can your exhaust systems mods. Using Premium gasoline can also hurt your fuel economy as your engine was not designed to take advantage of the extra detonation resistance.

And winter-blend fuel requirements apply to premium as well as regular fuel.

check basics.

tire preasure.
air filter
ox sensor (can cause a drop if fuel )
run injector cleaner thru a couple of tanks.

do no run preium fuel. it's not required and only cost you more money..

Well, my mpg is still good, but have never experienced loss of mpg due to using premium.
Money loss, yes, but never mpg loss. Luck to the OP

It's winter, OP; are you driving in cold or very cold weather?

Any loss from running Premium fuel will be minimal to the point of not being measurable without running the engine on a dynomometer; what it will not do (for a car not designed to burn it) is improve fuel economy.

running premium on a honda not designed for it.. will offset any problems that is hurting the engine atm. whether it is dirty injectors.. a drop in milage... bad spark plugs... just simple stuff that in return is hurting your engine but has not been fixed yet. it is not suggested to run on premium only.. but it does result in a healthier engine and a extra 5bucks a tank means nothing.

live in jersey. deff had a nice drop in temp the past few weeks. started before the cold really set in though. winter gas sucks -.- curious when it starts though. engine runs hot but more efficent milage wise during the summer

running premium over reg makes no difference, except for the extra additives they add in premium. they can only benefit you even if its not noticable.