Not sure what’s causing this to happen this year, but last year when I use the AC idle was steady. Now this year it’s rough and drops a bit during idle only. I did add a cat-back and CAI few weeks ago. Don’t know if the CAI or cat-back exhaust is doing this? Anyone know?? I have appointment for my 10K service this Monday and not sure if the service advisor will say it's because of the CAI or exhaust.

 

Could you describe the issue a little more? Also, what intake / exhaust do you have?

 

i asked this a while back and here is the link.
https://www.scionlife.com/forums/sho...light=rpm+drop
from what the responses i got it seemed to be quite common and regualar. but it is no doubt distrubing to feel the car shake and feel like its gunna stall out.

 

My bad… I have Descendant CAI and Megan drift-spec exhaust. At stop lights it drops to maybe ½ RPM (I can’t remember if normal is 1K RPM) and fluctuates between ½ to 1K while at idle. The most I drove with AC on this year so far is maybe 15-20 minutes or so before turning off car.

 

Snap... I don't know how I missed this?! Thank you!

 

500 is what I find to be the rpm that it sits at when it's 'warmed up'
Mine will rise to about 900 or so when the AC is on. But drop back down to 500 when it turns off.

Normal behavior if you ask me...


Stock engine and exhaust parts

 

It's completely normal. It's just the A/C clutch cycling on and off.

 

It is normal, there is no issues, once veh get to operating temp, it drops idle. I dont have either and mine does it as well. It is when the a/c clutch cycles on and off.

 

No problem man, it worried me too when i first felt the vibration and the rattle