2008 Fit Sport starting funny (misfiring?) - Honda dealership can't figure it out
 

I had my winter maintenance back in September (Maintenance Minder B15) . Since then, I've run into two major issues:

- The first issue was, upon accelerating, my car would make a scraping-like noise. It took Honda an entire month to figure out that it was the heat shield, and they removed it. Problem solved.

- NOW I have a NEW issue that has been happening since the beginning of October in which my car will start funny/misfire. It's almost like a weak start. I randomly went to Honda last week with a flat tire, and lo and behold when I was there, they suddenly couldn't get the car to start AT ALL. They jumped it, which started it successfully, dealt with the flat tire, and then moved onto the starting issue. They ran diagnostics on it, but no error codes came up. So, they recommended replacing the battery (even though the battery was testing normal) as it was 3 years old and said I'd probably need a new one by next year sometime anyway. I THOUGHT that fixed the problem, but once again today, I ran into the issue where my car started funny/weak. Once the car is actually on though, it seems to drive ok and I don't have any other issues.

I also had spark plugs replaced back in January, and engine air filter in Sept (after I pointed out to them that it was "bad" on the list they gave me, and they never bothered to tell me.)

I'm frustrated because I didn't have any issue with my vehicle whatsoever until I had my maintenance done in September.

I know I should probably take it elsewhere, but I've shelled out $3,000 going back and forth to my Honda dealer trying to get this issue resolved and keep paying for service and things that are not fixing the problem, and they also have a "100% satisfaction guarantee" on their website, so in my opinion they need to honour that and actually find and fix the problem. At the same time, it shouldn't take 4, 5 visits to get this looked at.

SIGH. Any opinions/suggestions would be helpful.

I would check the starter and check the coils. How many miles are on the vehicle?

If they replaced the battery and spark plugs at Honda I would check that. Make sure the spark plugs are torqued properly. Check the battery terminal connections for corrosion or loose connections. Check the grounds for corrosion or loose connection as well. If there is no error codes this would probably eliminate things like oxygen sensor. Check the vacuum lines for cracks or leaks.

You would also want to check the function of the fuel injectors and fuel pump. Beyond that you may want to check for valve lash or have the valves adjusted.

There's a lot of things you can check and it's strange that there is no error codes. It's hard to say if I can't inspect the car in person. Have those things checked and report back.