I have a 2020 LX 6MT w/3,000 miles. When the engine is not fully warmed up, (running <10 minutes), and I'm accelerating at half throttle, it has a lumpy power delivery (similar in feel to a misfire) in 2nd and 3rd gear, but only in the lower rpm. I will shift between 2500 and 3000 rpm, so once the clutch is fully engaged, the engine is only going 1700-2000 rpm and I'm applying half throttle. Once the engine fully warms up, it is smooth as glass under the same circumstances. If I back off the throttle, it runs smooth again. If I shift at 3500-4000 rpm, I don't notice it. It also doesn't happen in 4th, 5th, or 6th, or while accelerating from 1st. It does this since it was new. Normally I just baby it until it's been running 10 minutes, but sometimes traffic calls for more acceleration.

I'm curious because this is my first 4 cylinder manual transmission car. My previous car was an automatic Volvo that had a 5 cylinder and it was always smooth at every rpm.

Is this normal? Does the engine just need to rev higher when its cold? Could it be the 87 octane gas? It's too new (I would think) for anything to be wrong with it. Thoughts, anyone?

 

My car does something similar but it’s not enough to bother me. I get a bit of the feeling of what happens if you drive without putting your right heel on the floor (pressing accelerator with a floating foot), but like 15% of the jerkiness. I’m running 91 Octane and I still get it so I don’t think its gas related. I don’t think its clutch slip either. I also have a 70a durometer engine mount so it’s not engine rocking (which feels similar, I’ve had that issue on my old TDI golf). I don’t *think* it’s an issue, I tend to shift higher in RPMs as I like to rev the little 1.5L out so most of the time everything’s super smooth. But I do notice that bumpiness at low RPM + high load, so you’re not alone.

 

So you're saying the engine stumbles a bit when cold and you have to rev it higher. The Fit doesn't have gobs of power on tap - adequate but no more.

If you were having trouble accelerating, different story, but if you just have to rev higher, I wouldn't be worried. That's just an engine warming up and not liking being pushed that hard.

 

Thanks for the feedback. I really wanted to hear what other people experienced. It sounds like I have nothing to worry about, and I just need to ride out the gears longer when it's cold.

 

It does sort of feel like it doesn't like producing a lot of torque when cold. I get used to driving it a certain way when its warm, and it doesn't complain. I guess I need to start shifting at higher rpm when its cold and I should be fine. I appreciate the feedback though.

 

i have a 2015 with approx 34 k and today i was just thinking it does exactly what you describe....its always been a bit "lurchy" at low rpm , cold, and acccelerating but it doesnt seem to be getting any better....(and im keeping a weather eye out for worse..) i think its a characteristic of the lean burn DI engine..pleased to hear a 2020 has the same "problem"...
i wouldn't worry chug ..sadly..."its normal" !!!

 

From what I’ve read on this site and from my own experience - ‘15 LX 6spd - as abnormal as it feels, I believe it’s normal for this engine/trans combo. I almost never notice it 1st - it’s so short you kinda blow right through it...I notice it mostly in 2nd, maybe 3rd, not after that. In my case, it only happens at a certain RPM, which appears to be about 2200RPM, at least on mine....a slight stumble like a momentary hesitation or a misfire...always at 2200, mostly noticed in 2nd....I either rev high enough that I’m above when I get into the next gear, or just ignore it, am used to it. Dunno if it has a physical cause or has something to do with engine management software, but I think it’s pretty common

 

it feels like a giant rubbery engine mount

 

Glad might not be the right word, but I am glad that others also have experienced rough stats. When this has happened to me, I was worried that it was me. That I wasn't giving it enough gas or misusing the clutch or whatever.

Now, that I know that it is somewhat "normal", I won't worry about it.

 

What is happening is the engine when cold does not have the O2 sensors for feedback, and is running in a open loop mode. The computer is adjusting air/fuel ratio by throttle position. Naturally being a DI engine, the engine will set the ratio lean when the accelerator is not being depressed beyond a lower percentage. It is usually felt in 2nd and 3rd gear. The ECM was reprogrammed after 2016 to negate some of this "stumble" out of the open loop mode but it still exists, its the nature of the engine design, and emission restrictions. Older PI engines had a richer mixture when in open loop mode. It especially is more noticable if you have coked up valves since they are restricted. Once the engine warms up then it can dial in the mixture more precisely, and the engine runs smoother.

It happens to my car ever so slightly, but not so bad where it is of concern since it goes away once you drive a few miles.