Hi folks, new here. My mileage was disappointing after buying my standard 2012 Fit with 35,000 miles, getting 28 to 30 mpg.
I drive conservatively, with easy starts and anticipation of lights, etc, not going over 60 mph and mostly city driving.
At 45,000 miles put in fuel cleaner (I think it was Lucas fuel system and injection cleaner). Immediately got worse mileage, like 26 mpg. Still the same poor mpg now after several full tanks of gas.
Thinking it knocked some goop loose, which now has clogged something further like an injector, and that I should double down on cleaner with a different brand.
Can you recommend a good fuel injector/system cleaner?
Or should I consider getting some work done? I've had the oil change techs recommend a fuel system cleaning.

Thanks in advance.

PS I have used my Fit as a mini RV, camping out of it for 10 days, and sleeping in the back when it rained (1 night, my wife has slept in the back 3 nights, using a 2' x 4' piece of 1/2" ply to bridge to front seat's back.) Have a tarp that pulls out from kayak racks to one side, to bamboo poles.

 

keep driving

report back 2-3 gas tanks later (with no more additives)

 

^ this. Really shouldnt be using additives. I averaged 30-31 mpg since new, there's too many variables at play to try chasing one or two miles per gallon. Fuel in 2009 isn't the same fuel we have now. There's more corn, less bang per combustion cycle so more fuel is used to compensate. If you want better mileage run ethanol free but that's hard to find in some parts of the country.

 

I'll add there's a reason why they recommend it, and it's because they want to sell you everything you can buy. It's unnecessary.

 

You’re likely going to experience worse mileage on winter gas as well. It’s probably just coincidence, but every low displacement vehicle I’ve owned has taken a significant hit in gas mileage during the winter. I once owned a 1990 Miata that would return 34-36 mpg in the summer and as little as 26 mpg in the winter under otherwise similar conditions.

 

Also, while 28-30 mpg isn't great for cities, it isn't bad.

 

My average on my 2012 is 32 summer, 27.5 winter. Sure, I do take more highway trips in summer, but that’s overall 80% city.

It has dipped slightly over time, as has perceived power. I’ll blame the valves; as it’s the one thing I can’t check without a backup car around to take the kid places. (Also, they’re making noise).

I would not pay for a fuel system service yet. What’s that entail? If they’re not changing the filter, all they’re doing is dumping in some fuel cleaner and you just did that part

 

I have already put several tanks of gas thru it. I appreciate everyone's input. I suppose its possible that the change also coincided with the weather changing, and longer times warming up the car. But it really seemed that I had a distinct drop in gas mileage of about 3 mpg since the additive. Would changing the fuel filter, or something else, perhaps help?

 

Check tire psi, otherwise leave it alone. Don't go by what the dash says your instant MPG is, it's inaccurate.

 

Depends on the age and condition of the car - I find my display to be a bit scuffed up and dirty.

 

Lmao, whoops

 

Some basic ideas in the thread below. They would include: new air filter, clean maf, clean throttle body and butterfly, clean egr/passages, check spark plugs which tend to loosen on the fit, clean check battery terminals/clamps and major power contacts (voltage drop test then clean if necessary), check battery/alternator. Valve adjustment often is indicated at low mileage so search threads here for more info. Check for vacuum leaks.

Winter blend gas may give lower mileage. Also the corn tax hits you as that "fuel" obviously does not contain much energy. I think you should be buying fuel from a major but opinions vary here.

https://www.fitfreak.net/forums/2nd-...ml#post1421301

 

Stop warming up the car. See if you get your 3mpg back :P

 

So if the contention is that usage of a fuel system cleaner, somehow resulted in clogging or further degrading the system, the hope here is further usage would fix the problem?
I have no idea, but I'm skeptical that the usage of an over the counter fuel injector/system cleaner would cause any long term damage.
I mean most of them are just packages of octane boosting detergents and additives. My understanding or thought is that any "goop" that would be knocked loose or "cleaned" would almost immediately be consumed by the explosion crucible of the firing pistons.

I think I would just continue to monitor my gas mileage and see what happens. If it doesn't continue to drop precipitously, and as long as the engine otherwise seems to be running fine, I'd take the path of least resistance here, and just keep driving, see what happens over the course of months.

 

I found that even with winter gas, if I block my 2 openings below the radiator grille, I still average about 36mi+ gal highway even here in eastern PA.
Tires are at 36psi and car has 159K miles on 5MT.
I use LukOil gas here for best results.

 

I have a 6000 pound pickup truck, FIT, and some motorcycles. The smaller the displacement the more variable the MPG becomes, in my experience. I don't have the answer but no matter what I do within reason the truck gets 16 MPG. The FIT varies between 27 local but 40 on the turnpike at 65 mph. Motorcycles can vary between 36 MPG to 65 MPG.

Point is that the FIT's MPG will vary depending on conditions / driving style.

 

Those are normal for city driving mode. It's what EPA specifies.
What are you hoping for?

Fuels cleaners can damage sensors and catalytic converter... gasoline has all the cleaning additives needed to keep system clean. Nothing else is required given adequate and timely maintenance.