Knocking/Rattle on start up.
 

Hey guys, I had a weird issue this morning when I started up my BRZ. Upon start up it made a knocking noise that sounded a bit like detonation but went away after a second or two. This was followed by a small ammount of knocking/rattling (quiet and only lasting 1-2 seconds) while driving down the street and then nothing after that. I've had my car since June 2012 and I have 32,000+ miles on it and this is the first time this has happened. I've had no CELs and my only mods are a Nameless axelback and a AFE intake that have been on the car for a year. Anyone else have this issue or had something similar happen? Thanks!

Just noticed this morning as well. Maybe its the colder weather. It was only knocking during idle in traffic. It went away after 2 miles.

same here.. This morning was the coldest I experienced with this car.
it was garaged and probably upper 50's in there when I fired it up..
It popped and ran rough for a second or two.. ran fine after it warmed up..
Had 2 hours worth of driving later and it runs fine.. First time in 4500 miles
that I heard it pop and studder.. not concerned about it.. but this is one
weird little engine.

Mine did this morning too. I read in some other thread that its the cats warming up.

If you fit a cold air intake you will experience problems in cold weather. If cold air intakes actually worked then manufacturers would install them. They don't work and they don't.

Same at 6pm tonight
 

46 degrees out had a rough idle for about 6-7 seconds then a kind of low pop that appears like it came from the back.

Went away after driving for 10-15 min

If that were the case then I should have experienced this last year since I installed the AFE intake in October 2012 and about 20,000 miles ago. The morning that this happened wasn't even the coldest morning this week and it hasn't happened since when it's been colder.

I recently installed a K&N Cold Air Intake in my BRZ and noticed the same problem on a cold start-up. My car only has 1300 miles and on it and I honestly thought it was the intake.. After taking the intake out and putting the OEM Intake in the problem didn't go away... If anything the noise actually got quieter. I'm taking it the the dealership in a couple of weeks and seeing if they know what's wrong with it! Glad to know I"m not the only one that experienced this problem. Thanks for letting me know I'm not going insane!!

This car has some crazy startup sounds in the cold, the exhaust is very loud for the first 10-15 seconds. And the engine itself is also very loud.

mine too..last winter and now this fall--->on cold days (below 50 degrees F), the engine starts very rough with an occl pop sound at idle. Once driving, everything is ok. The twins just hate the cold! (like my wife!)

My car will be going back to the dealership this afternoon for the cam plate/oil leak issue (again) and I'm going to have them look into the knocking on start-up. It hasn't made the noise since but I'm hoping that they could at least eliminate detonation from the list of possibilities.

i'm guessing cold weather too. mine does it after sitting outside at work in the parking lot all day, but not in the morning in the garage. kinda bothered me the first time.. though after a couple blips of the throttle it goes away and doesn't return.

Popping sound in the cold is probably from your DI seals shrinking.

Any update with the knocking in the morning? What did the dealer say?