Need help P0300 & smoking exhaust!?

rjs_speed3

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MazdaSpeed3
hey guys, im having a pretty stressful problem. well, about 3 weeks ago i got an oil change, and ever since then i've been having smoke just puff out of my exhaust every once in a while. well it's only happened twice, but each time it was an extreme amount of smoke, white smoke, kinda smelled like "brand new carpeting".. lol that's the best i can describe the smell.. not to mention my CEL came on about 4 days after i changed the oil.. diag read P0300, mutiple random missfires. so go to start my car today to warm it up after work, after about 10 mins at idle i start moving and see in my rear and side view mirrors that there's an enormous amount of smoke, i change the spark plugs about an hour later in hopes to "cure" the CEL and hopefully see if it helped with the smoke.. the car seemed to run a bit better, but didnt fix the smoke problem.. the smoke seemed to have dissapeared tho once i got onto the highway, and hasnt come back since..

i was wondering if any of you have ever experienced or have any input or info on what the problem "might" be.. i was told that it "could possibly" be a blown head gasket.. i've had my car for about 43k miles and havent had any problems with smoke or turbo, and have had a test pipe and corksport cbe for a while and no problems, only now i do.... any hopes on narrowing down the possibilities of what could cause the smoke would greatly help me.

thank you guys in advance!!

-RJ
 
Check the seals on your turbo. I have the same smoke after I really start to boost and go into vacuum between gears or when I hit the throttle again after a gear change.

Quick way to check the blown head gasket theory is to put your hand right behind the exhaust pipe and lck your finger. If it taste sweet then then it is very probable.
 
BUMP
how do i check the seals on my turbo? (sorry for such a dumb question) it seems pretty hard just getting to the turbo... my exhaust just has dirty watery condensation... when my exhaust was smoking, it did smell somewhat "sweet"

the smoke just barely comes out now, only when i give it a good rev, it comes out when the rpm drops after the rev..
 
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Pull the pipes off the turbo and look for signs of oil on the turbo itself. If that is the start of bad seals, you may start to see trace amounts of oil in the intercooler piping.
 
it's only happened twice though... it has never happened again so far..... don't blown turbo seals smoke all the time? also don't you lose boost pressure??
 

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