I've noticed my 2016 Fit will "stumble" a bit when stopped/in drive -- but only when the AC is on. When the AC is off, it doesn't do it.

I plan on taking it to the shop but thought I'd ask if anyone has seen this before. I'm about half way through a 93 octane tank with injection cleaner (trying to rule out bad gas as best I can easily).

I'm getting great gas mileage and the injectors were recently replaced.

There is no check engine light. Just very mild to occasional harder "misfires" when the AC is on.

(And the AC is staying on in this heat!)

Thanks!
Steve

 

I'm wondering if this is a normal variant. Every time the A/C compressor kicks in, there will be a slight drop in rpms initially as the unit draws power away from the engine. Compressors on small cars like the Fit have a huge challenge, cooling all that glassed area with a relatively small engine.

 

Why did you have to replace the injectors? Using premium gas is not cost effective, psychologically, maybe. I'm surprised you had to so cautious to get the Fit to run right. I have a 2017 LX CVT with almost 36K miles on the ODO. I have done nothing but changing the oil/filter so far. I put in the cheapest gas. The car runs perfect. The only complaint is yes, the AC could be much stronger for hot and humid conditions. Do you have the Fit in Eco mode? Take it off. If you have a CVT put it in S for steroid and wow, the Fit runs like a champ.

 

I had the injectors replaced under warranty because there was some misfires and the check engine light would randomly light up. I'm now outside of warranty but probably within a grace period if the stumbling is due to the injectors (maybe).

I don't typically put premium gas in my Fit. I did it for this tank to potentially rule out a variable; bad gas. I'm just trouble-shooting.

The car isn't in Econ mode.

I should have stated that I've owned this car since new. So this behaviour is new and not typical.

Thanks!
Steve

 

Probably carbon build up in the values/injectors again? Do you a lot of city driving? My assumption is stop and go traffic creates sludge deposits from the constant hot/warm/cold temperature change in the combustion chambers.

 

I seem to remember reading here about 2015s needing both the injectors and the rail. If you had the injectors replaced but not the rail, might still cause issues. I don't remember specifics, but that's the first thing that came to mind.

 

OP indicated he has a 2016. Are the 2017 Fits OK without issues. Replacing them is a costly proposition.

 

I don't see any issues with the injectors here - no codes are being thrown up. How much mileage does this car have? I'm asking from the perspective of the spark plugs.

 

A small dip in RPMs is normal for a small engine like this when the compressor kicks in. Also normal for the engine to make a little less power to the wheels when AC is on. Enough that you could notice but not enough it would feel like it isn't doing the normal engine thing of making car go. For the engine to stumble though .. that shouldn't really happen.

 

You're right, my bad, was thinking of a different post.

 

Try driving it for a few days without using the AC ….easiest way to determine if it's something else or the normal "drag" of AC on a small engine. It won't kill ya to dirve a few days straight with windows down and just fan on. If the problem goes away, it's just the AC cycling on and off and the associated drag on the engine. If it persists, then it's something else.....easy troubleshooting to that point, anyway

 

Thanks guys. I'm going to just keep doing what I'm doing until something gets worse. It's just behavior that appears to be new so I was thinking of being a bit more proactive. There are no CE lights but when it stumbles a bit at a light, it can lurch a little if you're not solidly on the brake. I'm a light braker with this car (always felt like braking too hard would be hurtful to it for some reason - LOL).

I have about 37K miles on it and it's mostly city type driving.

When I have the AC off, it's smooth as butter.

Steve

 

AC drag on smaller engines is very noticeable. I had to get used to it when I bought the Fit after driving a 4Runner for 11 years. The 4.0L in the 4Runner doesn't miss a beat when the AC is on.

On the Fit, another thing I noticed is the hesitation is more pronounced when in ECON mode. It just started to get hot enough in the afternoon commute to need AC to be comfortable so I turn off ECON. The morning commute is still comfortable enough with the sunroof and windows cracked that ECON stays on.

 

I'm happy to report the stumbling is gone. Maybe the fuel cleaner/93 octane did the trick after a couple of fill-ups? No idea.