My car has a 3 year Toyota warranty. But both the Toyota dealer and Toyota headquarters said a horn is NOT COVERED UNDER TOYOTA WARRANTY....lolol do you believe it....
When i brought the car to toyota..the service agent asked if the car was in any collisions....i said NO....after the service the service agent walked over and RUDELY said ..the car was in an accident because the service attendant found new autobody work so now you have to pay a $130.00 dollar diagnostic charge plus $ 1.56 for a fuse...he said also that if the fuse blows again you will have to bring the car back to toyota and pay for more diagnostic charges to find out what is causing the problem..he said the car might have an electrical issue...
After i left a few days later the horn fuse blew out again...but I did not take the camry back to toyota. I called the insurance company of the other driver who was at fault and filed another claim....when I brought the car back to the Autobody shop..they said that it is one of the 2 horns that have shorted out . And there is no electrical problem with the car and that the horn should be covered by Toyota warranty...... lolol. See what I went through...

So the mechanic disconnected the shorted out horn..and the low horn worked for weeks while I was deciding what to do while calling up toyota begging them...I TOLD HEADQUARTERS NO MORE TOYOTAS AFTER THIS CRAP I CAN GO TO ANY OTHER CAR COMPANY COMPETITOR FOR this crap.........i called insurance and filled another claim on the at fault drivers policy not mine...the non Toyota mechanic replaced the horn Toyota should have paid for.....
I just noticed low idle recently but it is slight
Also this corrupt Toyota dealer had just changed my cars oil just before the accident...they did a 10,000 mile synthetic oil change...i wounded if they screwed up the idle when they changed the oil or did not clean something at the change...

 

Did you every get your issue with the idle resolved?
I have a 2016 Camry SE that does the same exact ruff idle thing as yours. I noticed it around 50k miles, I it has approx. 60k now.

Funny thing I have the same issue in my 2007 Camry LE that I noticed at around 75k miles.
They are different engines but same rough idle while idling in drive. It is more noticeable with the a/c on.

The 2007 has 290k now and still does the same thing. I haven't been too worried it because it never died on me sitting at a stop light or in traffic.

I would appreciate any more info you have on your rough idle issue.

 

Try cleaning the throttle body.

 

I was hoping Deeboy might respond about his 2016 Camry.

Thanks toyomoho but I really don't need your input unless you can give what I asked.