Problems with stuttering/sputtering

[Deeone14]

I have had an ongoing issue with my 21 GT2 AWD. During the first 10 minutes of driving, the car stutters and sputters when I accelerate. It also feels like the car drifts left during hard acceleration within this time period. After driving for 10-15 minutes, the car starts accelerating and driving normal until I shut off the car and restart. Once I restart, it acts like it did at start up for 10+ minutes. I don't have any check lights on. My car has 67k miles and I have the stock ECU and TCU. Has anyone else experienced this before?

 

[Snicklefritz]

first off, you ought to not engage in 'hard acceleration' in the first 10-15 minutes. let the drivetrain obtain full operating temperatures before giving it the beans. as for 'drifting to the left' that could just be your sensitivity if it apparently goes away after warming up. but I don't know, maybe AWD when still warming up engages front to rear differently than when warmed up. I couldn't say, because I do not do hard accelerations until my car is showing oil temperature right around 200F. I'll do brisk accelerations, engaging the turbos, but only to c. half throttle until then. as for stuttering and sputtering, the first things you always check are plugs and coil packs. once those are ruled out, if it continues, it's got to be something electrical/sensor related that regulates fuel and air mixture. others with more experience can chime in.

 

[socalvn]

Hot or Cold it shouldn't shut or sputter definitely beter on the car laying into it after reaching operating temperatures.
Not sure what's causing your issue

 

[Deeone14]

I always warm up my car for 5-8 minutes before driving each day. My hard acceleration meant merging onto the freeway and launching at a dead stop. I thought about the plugs and coil but I doubt they would start to run smoothly after driving if they were truly faulty or broke. In my past experiences, faulty plugs/coil sputtering never went away after driving for 10 minutes. I'm stumped.

 

[Snicklefritz]

my one experience with bad plugs was caused by a bad coil pack, it kept ruining the new plugs. at first the stuttering was very mild but noticeable under boost. But if I would do WOT it seemed fine most of the time. this persisted for nearly 4,000 miles and finally I started seeing the CEL when I engaged boost and it wouldn't go out until I shut down. If I drove sedately without boost the car felt completely fine. But your issue sounds different with stuttering happening regardless if boost or not and fading going away after fully warmed up. you still check plugs and coils though troubleshooting.

 

[Alpinesting]

This is interesting. We have the same issue. The one thing that we do know is that it is cylinder 2 and after having
the plugs replaced it went away for a bit. However, it has reared it's head again on the same cylinder which tells
me that it's a bad coil pack. This car has 16k on it and after doing a lot of research it seems that a simple coil pack
replacement will do the trick. Btw 2021 gt2. Now, every mechanic has told me that when one coil pack goes bad
then you should replace them all. I'm not sure if I should replace all the coil packs after having the plugs replaced and
using a code reader to isolate the problem. Love the car, but this is getting crazy.

 

[Snicklefritz]

Now, every mechanic has told me that when one coil pack goes bad
then you should replace them all.

You would expect a dealer to be "every" mechanic. But the dealer replaced the one coil pack and never suggested anything more. It has been several years now and I have had no trouble on the one replaced coil pack and 5 original ones.

 

[Alpinesting]

Thanks for the response. It is really funny, I called the dealer today to confirm our recall service for the oil feeder for the drivers side

turbo bank which we made weeks (nearly 4) and they said that they didn't have the parts for the recall. Now, for us, this is really weird

because they actually called us nearly 4 weeks ago and said we have the parts and we will schedule an appointment etc. etc. on the

23rd of this month. The only reason I called them today, one week out, was to add a coil pack replacement and an inspection of the

number 2 spark plug which they gladly added to the appointment. Having said that the parts guy and the service person had a

meltdown trying to figure out what was going on. Thankfully, after getting several texts confirming our appointment we were assured

that the parts were at the dealership. There seems to be a communication problem with this dealership and staff. It was really odd

as the parts guy didn't know where cylinder 2 was on a 3.3. Yikes KIA!