Fucking terrible MPG and power

I have a '09 Fit with 105k miles and it's been a complete dog the past couple of months.

In the summer it usually gets around 35-45mpg at 60-80mph, but recently it's been getting 25-27mpg entirely in highway miles, even drafting behind trucks and averaging around 65mph.

Torque Pro says it's getting a consistent 60-70 wheel horsepower on average with the standard test.

Air filter is brand new. Every single fluid in the car is brand new. Torque shows completely normal values and no codes of any sort. The only maintenance I haven't gotten done is valves and a fuel filter.

Is my car just getting booty blasted by the cold or could bad valve clearances / an old fuel filter cause this shit? I love the car, but the poor thing can't even spin one tire on dirt anymore.

Cars have worse mpgees during the winter, its to be expected.

I would replace fuel filter, especially at that mileage. Cant hurt. Also, check that the o2 sensors and MAF sensor are good/clean.

winter blend gas
where do you live

...

Winter gas mileage. It's a thing. My IS300 dips below 20 mpg in the winter. Complete fucking hog.

Clean/ replace EGR valve.
Clean / replace spark plugs and replace coil packs
Check your God Damn battery
Resign yourself to the fact that winter blend gasoline is garbage and try again in the summer months.
Run some sea foam in that bitch
Buy a high quality air filter

>09 Fit
Found your problem

Probably an o2 sensor, my mpgs were cut in half when one mine went ou.

Those digits. Rekt

You ever replace the spark plugs? At 100k you should check the tune on the fuckin thing if you haven't already. (spark plugs, fuel filter, get a decent air filter, tire pressure) check ALL the simple/cheap things you lazy shit.
Also if you've been playing around in the dirt in that thing and all you're worried about is gas mileage then I just dont know what to do with you.
Also the valve clearance on Hondas need to be readjusted like every 30k or something.
Lern2maintain

So when was the last time your dumb ass checked tire pressure?

Quads have spoken. You need to walk outside right now and set that '09 Fit on fire. Post pics.

>Not turning off climate control, during winter, for higher mpg.

Are you even trying?

Heat doesn't use a/c, no point.

These.

Winter blend gas, the car has to cut through denser air and warmer intake air is better for mpg.

I have an 08 fir and after 140k i started having the same problems, despite replacing fluids and such as well as regular maintenance. The culprit was a bad spark plug coil. I bought 4 for 300 shekels and did the trick. Google this shit its a common prob

Is winter mileage realy a thing in germany?
How moch worse is it during winter?
I got my first car last autumn and get about 60mpg on a tank, is that bad for winter driving?

FWIW: They don't need adjusted that frequently.

Honda recommends checking and adjusting clearances at 30k, buy I rarely find one that needs a single valve adjusted. The factory spec is fairly wide.

Coolant temp sensor, too.

Not the sender, the sensor.

oh shit i forgot to check this thread because I would have thought it'd 404

Michigan, no idea about the gas

Spark plugs and filter are brand new, tire pressures are OK (40psi ish on knobby Winterforces), but haven't checked valves, EGR, O2 sensor (the A/F ratio reads fine?), or coils

When I installed spark plugs, plug #3 was barely in there finger tight and was completely covered in soot but didn't think of the coils

Thanks anons, I guess I'll be getting some replacement gaskets and some feeler gauges to check everything over

Coolant temp sensor and O2 sensor seem to be normal by how the spark plugs look and how the car warms up (no different from when I bought it), so I'll check those too but I don't think those are much of an issue.

MAF is probably dirty though because after every single event my air filter comes back as a solid mass of mud and grass

You ungrateful fuck. My shitbox trailblazer gets 13 city year round.

>not doing valves

i did this once. burnt a valve in cyl 3. my mpg dropped from 24 to 16 and my truck got so slow I was WOT in city traffic and highway and could only use 5th gear downhill. better check your valves nigger.

>13mpg city
Dafaq
What car do you drive?

>What car do you drive?
>My shitbox trailblazer

C'mon man.

>How moch worse is it during winter?
See pic related in , I tracked it all year. In the worst vs the best month I lost about 15% in economy.

I've already listed multiple reasons why every car takes a hit in mpg in the winter.
Also, your car is in open loop(dumping fuel to warm up quicker) a lot longer, and more idling in general for most people.

Could be a few things...

Valves

Worn cam lobes

Valve clearances

Stem seals

Piston rings

Spark plugs may be new but did you check the gap on them? I've gotten some new from parts stores that were pretty far off. Also dont go cheap on plugs, get yourself some NGKs if you haven't.