2015 Lacrosse Engine Shutter idle

[KShaw]

Hello everyone, I recently bought a 2015 Lacrosse 3.6 with 48k miles. I'm experiencing an engine shutter/vibration only while at idle. The car can be both in park or drive when I start to feel it. Sometime when I start the car I won't have a shutter then once I get back in 30mins later it's there.
I brought the car to the dealership and they said they "couldn't recreate the problem."
Also using more electronics I.e. AC, Lights, seat heaters...etc doesn't make the car shutter more or doesn't create the shutter.
I thought maybe it's bad gas? Or spark plugs?

If you have experienced this I would love any feed back! Thanks

 

[Rich B.]

Just happened to be viewing this early, so...... Sounds like as you stated, a cylinder borderline misfiring. May be coil and good chance a code is present to assist. Long ago would have engine running and would remove plug wire one at a time to see if idle got worse or no change. Even a plug boot not fully seated.

Wouldn't put fuel out of the equation either. Don't believe anything as TPS or MAF is at fault because it's a skipping and not anything constant or variable🤔

Forgot, I used to use high voltage fuse pullers removing and reseating plug wires with engine running.

 

[2007LucerneCXL]

Not picking on the service shop as you would know them better, but it's not uncommon for them to scan it and then test drive it for 5 minutes saying they can't reproduce the problem LOL. Intermittent problems are difficult to find but simple trouble shooting can eliminate what isn't causing the problem.

A top tier injector cleaner may be a option, certainly can't hurt. Check that the intake hose, clamps and filter are properly fitted, vacuum hoses are installed properly, make sure ignition system is in good repair plugs and wires.

Other items can possibly cause this, mechanical or electronical, but it's tossing a bunch of wild guesses hoping ones stick.

 

[Fcar1953]

My 14 is not as smooth when i burn Regular fuel. I run high test more often than regular but i do change off. i can always tell when I'm running regular, not as smooth. I burn Costco fuels they only have regular or high test. I guess ill get my butt flamed because i brought up hight test fuel!!!! It is the 6 cylinder.

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[tombalas]

My 14 is not as smooth when i burn Regular fuel. I run high test more often than regular but i do change off. i can always tell when I'm running regular, not as smooth. I burn Costco fuels they only have regular or high test. I guess ill get my butt flamed because i brought up hight test fuel!!!! It is the 6 cylinder.

Using premium cannot hurt, but I routinely buy generic unbranded 87 octane regular for my 16 with a 3.6, and no issues at all thus far at 35,000 miles, so I'm sticking with the cheap stuff.

 

[cbragwel]

Isn't the 3.6 rated to run on regular 87 unleaded?

 

[Fcar1953]

Isn't the 3.6 rated to run on regular 87 unleaded?

If you read your manual, it states 87 or higher. Like I said before. I don’t use 93 all the time but most of the time.

 

[Fcar1953]

Using premium cannot hurt, but I routinely buy generic unbranded 87 octane regular for my 16 with a 3.6, and no issues at all thus far at 35,000 miles, so I'm sticking with the cheap stuff.

You do what ever you like, I’m not telling you to change what you’re doing

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[Rich B.]

Yes, mileage is better with higher octane fuel due to the engine can advance timing further without signs of predetonation or pinging/knocking.

We use the 87 octane with ethanol no less and mileage is horrible, but it's Maine.

 

[richardnewton]

We use the 87 octane with ethanol no less and mileage is horrible.

That ethanol is terrible. We have no business putting corn in gasoline.

Just a massive transfer tax from working families to the big corn farms & genetic engineers. And horrendous for the environment.

Unfortunately, neither party has any willingness to touch that tax with a barge pole.