04' STI, need help ASAP.

[DoloSoLow]

I'll try to explain this with as much details as possible since I do not have any photos or video. 04'STI, 148k miles stock.

Well, this has happened a few times but has not occurred in a while so I assumed it was fixed. Yesterday after turning off the car and heading to BK, when I got my order I left. When I turned on the car it began to shake and then I noticed smoke coming from the right side of the engine bay. I immediately turned off the car and back on again, same thing. So I decided to wait a while and then it went back to normal, I still drove home very carefully.


** This happens basically within the same time frame 5min; turn car off, leave for a few minutes, turn back on -- then noticeable shaking starts with smoke coming from engine bay.**

I just really need to know what this is before it gets worse, also can it be that my brother accidentally put 89 octane gas instead of 93 a few weeks ago (I quickly changed the gas, since I noticed knocking noise meaning he put wrong gas, which thankfully the noise is slowly reducing).

EDIT -- I found a video of how my idle was everytime this happens, only thing is the car in the video is a WRX. I was looking for another one but with a STI, no success.



Thanks everyone for the help

[teflon_jones]

Let's start with what mods the car has. Is it stock?

[DoloSoLow]

Yes, its completely stock.

[Donkey]

Well if it doesn't have a CEL then it could be alot of things. Maybe it just needs new sparkplugs or the MAF cleaned. Check to see if anything is loose/cracked on vacuum hoses and intake track. Clean and retorque the engine grounds and battery terminals. With any substantial data its kinda hard to diagnose of the internet.