With a scanner that can look at live data you could check the misfire counter to see if it's a particular cylinder or random.

Other than that, when was your last Italian tune up?

 

Good idea. I'll get the scanner out of my cargo area and have it handy for when it starts vibrating again next time. I have accelerated somewhat briskly a few times in the past few months onto the on ramp of my local interstate. But probably not full-on Italian style though.

 

I wonder if it might be some sketchy gas? What oil do you use Hank & when's the last time you ran Techron through the tank?

I would have the occasional rough idle with my 2014 too. Since switching to Restore & Protect, it's gone. But it's also only been warmer weather (meaning summer blend gas & no really cold engine) since using it.

 

Hey Geo - I typically fill up at Costo or the local Marathon here (both Top Tier and I will run Techron every 12-14K miles). I just used up my last Kirkland 5w-20 Full Synthetic, will be switching over to Kirkland 5w-30 FS in the next couple weeks.

 

Spark plugs and air filter were changed 20K miles ago

Just curious, where did you buy the spark plugs? There has been a “counterfeit” plug problem on Amazon and eBay.

 

I got a set of NGKs from Amazon. Not sure if I can tell at this point if they're counterfeit.

 

If fuel system cleaner or an Italian tune up doesn’t help, I’d pull the plugs and inspect them to be sure. NGK counterfeits tend to wear very fast.

Here’s a site from NGK to help identify counterfeits.

Counterfeit spark plugs: The ignition villains that could ruin your engine!

NGK SPARK PLUG advises on how to beat the counterfeiters. Fake spark plugs can do serious damage to cars and businesses.

www.ngkntk.com

I'm due for my annual/12-14k mile Techron service so that'll go in my next fuel up.

What I mean is, if counterfeit plugs is the source of your problem, I would have expected the symptoms would have happened sooner and been more obvious/severe.

I still would be pulling one out to inspect ASAP.

It's been approx 22k miles since I put the plugs in so hopefully they're not the culprit, but I'll pull a couple out tonight and report back. If they check out, I hope Techron and/or Italian TU will do the trick!

Thank you all!

 

I removed all four spark plugs, gave them all a wipe down and examined them all very closely with many images from the website rhysoul posted (as well as others from Google), and I'm fairly certain that mine are genuine NGKs. No subtle or glaring signs that they're counterfeit that I could see. I did however, manage to break a black plastic tab from either the wiring harness clip to the ignition coil, or to the ignition coil itself (was easier to pull the coil out with disconnected wiring on the coil next to the fuel line). Hopefully that won't cause any issues as the clip to the ignition coil is not as tight now - maybe it's a good time to get new coils (overkill?).

 

That’s good they seem genuine. It’s risky these days buying “genuine” auto parts from eBay or Amazon (unless you’re sure they’re an authorized reseller) that I don’t bother. Rock Auto has been pretty good though.

If it’s the little plastic tab on the coil connector, they do break pretty easy. I broke one last night, but the connector still kinda clicks in when attaching it to the coil.

Flatsole has a thread showing how to repair it using an inexpensive harness from the older 1.6L.

https://www.kiasoulforums.com/posts/1343170/