Intermittent misfire on cold start

Tiny
DEV IMVU
  • MEMBER
  • 2018 ALFA ROMEO GUILIA
  • 2.9L
  • V6
  • TURBO
  • 4WD
  • AUTOMATIC
  • 9,000 MILES
Hey everyone, the story started before 3 months still dealership can't figure what cause of that misfire( only cold start). It's randomly sometimes the car runs perfect for 2 weeks no misfire cold start. They did everything; changed sparks, coil, they did test every units, injectors, evab, fuel pressure. They said everything normal, the misfire mostly came after refill the tank next morning. They checked the fuel cap also no issue with it. I'm so confused. Any suggestions?
Monday, January 4th, 2021 AT 2:47 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,256 POSTS
I would run the codes to see what comes up but to me it sounds like the engine coolant temperature sensor may be out of range when cold. Here are guides to help us see what's going on:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

and

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

and

https://www.2carpros.com/articles/how-a-coolant-temperature-sensor-works

Let us know what happens and please upload pictures or videos of the problem.

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Wednesday, January 6th, 2021 AT 9:32 AM
Tiny
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  • MEMBER
  • 2 POSTS
Hi Ken, the cold start misfire only came on cylinder “1” this is the 5th the scanner code found only happened with that cylinder, however dealership roday told me they going to open the engine head to have a check and take some diameter of some part as the factory requested that, and then they will confirm to replace the entire engine ! I'm surprised how they could think about that while the car run perfectly except that random cold misfire. I'm still thinking which internal part can cause a cold misfire.
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Wednesday, January 6th, 2021 AT 9:56 AM
Tiny
KEN L
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  • 47,256 POSTS
Good call there. I would thinking an injector would be more likely. Can you please let me know what happens and what they did to fix it when you get it back?
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Thursday, January 7th, 2021 AT 11:11 AM

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