TurboTJ

I seem to be getting quite a bit of jerking and stuttering on my 2015 FE. It happens a lot when going from slight engine braking to very slight throttle. The car hesitates and jerks forward. It seems to do it around 3k RPM's in 2nd-5th (may do it in first also, but I haven't noticed it) It behaves completely normal under all other situations though.

The car has 1200 miles and is 100% stock.

I've also found that it is averaging 24MPG over the life of the car! My 2013 MR averaged 20.1MPG over the 40k miles I put on it (I log the fuel every time I fill up, so this is pretty accurate). Today, I drove 300 miles in the mountains and averaged 26MPG (verified by the pump)! This lead me to thinking that Mitsubishi built in some "lean cruise" mode that the car is oscillating between during the stuttering - Has anyone else noticed the same thing?

Any ideas on what could be causing this or where I should start troubleshooting? I would take it to Mitsu but I doubt they will have a clue where to start since there's no CEL.

Thanks for the help!

Napalm_Enema

I'm not a fan of the factory tune from what I've read on the FE. I think you would resolve your problems with a proper pro tune, or just flash a good established base map for your car, however you may want to avoid voiding the warranty which is a bit of a catch 22. I did, when stock, smooth out a stumble in my higher RPM band on my MR by adding a Cosworth air filter, just a simple drop in that doesn't require a tune. It smoothed that out and the whole range felt cleaner for lack of a better term.

You can check with your dealership if they have any other flash updates in the mean time as well.

Update with your findings and if you get it resolved!

Dandbest

No issues with mine, but I also have never seen fuel consumption like yours, and I drove my car from Georgia to New York, 900 miles in one day and averaged 23mpg which is inline with my 2011 and 2014 previous Evos. I'd mention it to the dealer and have it scanned, as soft codes don't turn on a check engine light. I don't buy the FE tune bs being spread.

AngryEvo

Same thing on my 15. Getting surge/stutter every time I press or release throttle. Stock too. Dealer on Tuesday. Will report back.

ChibiEvo

I didn't notice any stutter during my drive home (approximately 330 miles). It felt smooth the whole way. The car is in the garage for winter right now though so I probably won't have any more confirmation on this for a couple months.

TurboTJ

Thanks for all the feedback. I'm thinking the only way to resolve this would be to do some logging to see if it's pulling spark, fuel, etc.

Is it really doing it every time? Mine only seems to do it under certain conditions. Like very slight engine braking to very slight throttle. I didn't even notice it for the first 100 miles I put on the car. Let us know what the dealer says.

My theory is that they leaned out the map for emissions and the hesitation is the ECU jumping between cells (or fuel maps) with very different values without using some form of hysteresis. I'm loving the extra 3-6MPG, but the occasional stutter bothers me though I'm learning to drive around it.

I guess it's time to purchase evoscan.

AngryEvo

I think mine feels more like a drivetrain issue as opposed to a tune issue. I could be wrong but I'm thinking motor mount or the like. And yes I feel it all the time in the lower gears. Just too sloppy to seem normal. Maybe even a sticky throttle plate. Who knows lol

CaptainCrunch

I hope Florida Mitsubishi service is better than in NYC/NJ.

TurboTJ

That sounds like it might be a different issue than mine. For me, it happens in all the gears, though it is nearly unnoticeable in the higher gears. Since it doesn't happen all the time, I'm not sure how they would even diagnose it. I just drove home from work tonight and had no issues. I did my first WOT pull ever after 1300 miles of engine break in, and she did amazing!

I doubt yours would be a sticky throttle plate since we are fly-by-wire throttle. I'm not even sure if there's a spring in there anymore and I'm guessing the stepper motor sticking would trigger a CEL.

I guess as some have mentioned, I will have them check for soft codes that may not set off the CEL.

I found some thread talking about a knock cal map being a little too sensitive around 2-3k RPM's, but I'm not sure if this applies to the stock tune. Retarding spark based on detected knock would definitely explain the symptoms...

Any other ideas?

AngryEvo

Dealer said my evo drives just like the rest of them. I test drove another to confirm. Lol

Napalm_Enema

Man the car needs a tune, as most cars the factory tune is garbage. Catch 22 with the warranty blah blah blah but I know it needs a tune, you know it needs a tune lol.

I think Subaru and others intentionally release cars with garbage tunes in order to make you void the warranty? Conspiracy theory ftw!

AngryEvo

You ain't kidding man. The service guy, who was cool and said he owns a ix, said don't mod it all all if you want to keep the warranty. Said they denied a transmission repair on an mr a few days ago with just a Cobb AP tune and a catback.

Napalm_Enema

I 'intended' to keep my car stock. But stock there was a horrible stumble at the high end, car just felt 'off'. Rolled the dice, had Kozmic do some basic things, now the car feels perfect as it should have from the factory.

I completely get not modifying it but I couldn't stop myself because the car driving the way it did annoyed the **** out of me.

TurboTJ

I don't understand. Can't we tune the car and flash it back to stock whenever we need work done at the dealership? They might see the flash counter incremented but that surely isn't enough to void a warranty.

Napalm_Enema

This is the pandoras box of he said she said they said. Some will say they can't tell, others will say they can. Others say Cobb designs things so they can't if you use them etc..

I would, if it were me, just flash a Cobb tune on there and leave it alone. Easy to remove easy to put back.

If you want to avoid that, for now, though I don't know if it will address your issue, drop in a Cosworth air filter and see if things smooth out for you. No tune needed, just lets it breathe a tiny bit better which I found to improve things quite a bit in my MR. Almost didn't get a tune because it really helped the stumble with just that part

Good luck.