My Honda DD only getting 25mpg??

[B18C5-EH2]

It could be a lot of different things as many have stated, but a few stick out to me:

You could have a vacuum leak

The coil inside the distributor could be on it's way out - not enough consisent spark = crappy gas mileage and breaking up under acceleration

Possibly rotor button, plug wires, etc. I suggest only OE Honda or NGK brand plugs/wires

Deteriorated 02 sensors - do yourself a favor and order them online and ONLY get Denso or NTK direct plug-in styles - Bosch suck ass for Hondas

Valve lash adjustment could be out - have the valves adjusted

This is an "shade tree bull**** mechanic" suggestion, but also try a new fuel filter - get one from the Honda dealership

Check your tire pressure - "what?" - yes I'm serious. Tire pressures can actually affect mpg

Believe it or not this is one of THE hardest things to properly diagnose and repair the first time. Since you have no check engine codes being stored it makes it much more difficult. I have a feeling hatever is causing your hesitation on the highway will throw a check engine light soon - hopefull for you it'll be really soon. That will be the biggest step towards better mpg IMO.

If it's a spark break down then you can see how that would cause bad mpg and stumbling, right?

Good luck! Keep us updated!

[Bpeterson]

hey does your gas light work b/c i thought the same thing in my 97 civic with a y8 but the gas light ended up not working and i hit the empty line at about 230-250 and i can still go to at least 310 - 320 just wait until you hit the end of your gas gauge fill a gas tank up and ride till it dies

[AznTraitor]

okay, so I replaced the o2 sensor today and it still bucks and surges....


but now, once the car is warm, from a stand still the car will bog heavily at take off??!

I'm at a loss on what it could be, as I've done the tune up, replaced fuel filter, seafoamed, and now o2 sensor!