My 2019 (75,000mi) Fit has had a string of lights recently and barely runs until warmed up. After warmup it runs albeit somewhat roughly. Gas mileage still reads 41 mpg. S far our mechanic has replaced 4 coil packs, replaced oxygen sensor, checked for vacuum leaks, checked Catalytic converter, and checked for carbon buildup. None of which has fixed problem. Code scanner shows misfire on all 4 cylinders and two fuel/air codes. Air filter is good.
Any next steps that may be likely problem?
BTW this is our 2nd FIT, our other was a 2008.

 

it sounds like the only thing left is the fuel injectors

 

You may not want to hear this but another mechanic should be in your future.

Plugs should be checked first (not to see if they're bad but to see if it's burning lean), then high and low fuel rail pressure. After that fuel trims and cylinder torque values need to be checked as well as DBW stuck ratio (throttle body carbonization). I'd almost guarantee a fuel injector issue at this point considering a heated injector is in it's expanded state, but this shouldn't have had what we techs call the parts cannon thrown at it and definitely should have been diagnosed properly the first time. All of this is doable within 2 hours time quite easily as well. Good luck and I hope you find your issue.

 

Has the mass air flow sensor been checked/cleaned? Otherwise others are pointing to fuel injectors and I'd have to throw my hat into that ring too. You could try a fuel injector cleaner.

 

After much consternation it turns out that all 4 injectors were bad. 3 were toast and one had issues. What can cause this? Fuel injector shop in TX said they were junk injectors and unable to be salvaged. Am I looking at 4 new injectors every 75,000?

 

Common issue on these cars.
IIRC, there was a Honda recall to have them replaced as well (or maybe mine were replaced due to being under warranty, I can't remember).

As a bit of solace, of those who had them replaced, none have experienced anymore fuel injector issues.

 

The replacement applied to 2015/16 injectors. His car is a more recent 2019 which should not have problems since it has the redesigned injectors. Of course there is always the possible issue of cheap gas and other factors. .

 

Honda has not solved the carbon buildup problem on the 2017+ models. We're still seeing reports of severe buildup / injector failure in engines with as little as 10K miles. That tells you something is still wrong on the design or manufacturing end.

In the meantime, my advice is to run Top Tier fuel only if you can. If you don't live near a Top Tier fuel station, things get much more challenging.

 

+1
Agreed

 

I'm into top tier too, but does that guarantee no injector problems? Is it that simple? Well, I guess I'll find out.

 

Let's get something straight. My 2017 LX CVT bought new, Nov 2016, 119K miles running on the cheapest gas I can find, ie, Walmart, Krogers, Pilot, Love's you name it, It it is "gas" it goes in the tank. My Fit runs perfectly fine. Still getting over 40 mpg on the highways. If you have issues with your car, it is not because of cheap gas, and my inductors work just fine.

 

https://www.consumerreports.org/cars...e-a7682471234/

Quote from the above link:

The results showed that on average, non-Top Tier gasoline had 19 times more carbon deposits on injectors, on intake valves, and in the combustion chamber than Top Tier gasoline.

 

Aren't facts wonderful? Thanks for your post.