ScratchedCornea

ghostrider990

You might need to describe what "rough" means in your terms, especially when comparing it to a WRX boxer engine. That's a huge difference, and off-hand, I'd say - your V-6 should never idle like a Flat 4.

I have noticed that sometimes I'd experience a bit of a "rough idle" in the 2.0t audi engines at start up, that I would describe as an imbalance in the cadence of the engines rythm, and always thought it was the motor mounts being "calibrated" as the engine warmed. But that's just a loose interpretation.....and not really applicable to our motor in relative terms.

Can you describe the sensation??
And as always - if you suspect something isn't correct with the car, you are fully under warranty - but they'll have to keep the car overnight to replicate the issue.

Where did you buy your s4?? Which dealership??

gr

mplsbrian

All new S4s have a little bit of a shaky idle when cold. It goes mostly away once the engine breaks in. It will never go away completely because a V6 is inherently a dynamically imbalanced design with an odd number of cylinders and counteracting the internal forces with balancing shafts is a challenging physics problem which you can read more about that here. However, once this S4 breaks in the shuddering and shakiness felt at idle subsides quite a bit, or at least so we've found.

This is good advice. It's impossible for us to feel what you're feeling but there is a good chance your dealer can sit in your car vs. any other S4 or S5 on their lot and tell you if what you're feeling is normal or not. But unless you tow it there, GR is right-- they'll need to let it cool off to a cold start and this means keeping it overnight. Not a big deal as you can probably drive an A4 loaner home and remind yourself why you upgraded to an S

ghostrider990

I had an 18 2.0t Quattro loaner (P+), and I was reminded how GOOD a car it is!!

With an APR tune and some other tweaks, it would be a VERY competent - compelling daily driver.

I really wish the S4 had an S-Tronic transmission.....sooooooooo smooth. ZERO engine braking though.....and that's a bit odd.

mplsbrian

Yeah, I guess GR is right. Even the most basic stripper model quattro A4 with zero nav or other tech is still an amazingly competent car, zippy as hell and with grip for days, but it just lacks the S4's soul. The exhaust, seats, and sport diff are what upsold me. I rarely use all the S4's power but I throw myself into its side bolsters and grin over the exhaust growl on the daily.

ghostrider990

I was EXTREMELY happy to get back in my S4 after having the A4 for the weekend, but I still don't love the Tiptronic vs. the S-Tronic.

It's completely unrefined and harsh in comparison - especially on the downshifts.

Now back to the rough idle: Keep Us Posted, and if you can post a vid, or add a more thorough description of the malady, please do.

gr

Mr.Meme Yo Girl

Its funny you posted this, I actually just noticed yesterday a pretty rough idle in mine. I got the car back in Sept of 2017, and occasionally have noticed a slightly rough idle but it wasn't too bothersome. but yesterday i was in my car (just parked in my driveway) and heard the passenger side seat belt hitting the side of the seat. I also could feel the car vibrating slightly too but when i looked over, the passenger seat was really shaking a lot visibly. like i mean shaking like if i was driving over really rough roads or something. that got me a little shook (pun intended). but i dont think the car should idle that rough. just for information my car is currently straight piped from the cat back (no mufflers or resonators) dont think that should really cause that but who knows. my car does currently have just under 10k miles so its definitely broken in by now

ScratchedCornea

HCGxKaLiBeR

Exactly the same as mine. Only during cold start the first minute.
The engine behaves like my LT1 V8 engine in my 16 Camaro.
No issue at all, but I'm just surprised that Audi's DOHC V6 is just as "rough" as an OHV V8. lol

India Whiskey Charlie

Not in my case. I come from 3 B8 S4's (2010, 2014 & 2016) and each generation was smoother and better than the one before. But, the Tiptronic in my 2018 is worlds better than the S-tronic in those cars. Way smoother shifting every which way but one knows it's an automatic and not an auto-manual and that's fine with me for a daily driver. Not sure how old your car is but it's worth checking if there's a software update at some point in the future.

As to rough idle, this car is also somewhat smoother than the B8 and totally acceptable given its character. If you want smoother, try a V8...