Sup everyone! First time ive ever posted in a forum so thank you in advance. So i have a 2009 scion tc that i rebuilt. Noticed the cylinder walls were worn so i had them bored out from stock to 89mm with 89mm pistons/rings. Everything fuel and air related is brand new either Toyota or Denso brand. The cylinder head is a reman from a reputable shop. Ever since i did all that ive noticed on live data im getting random misfires at idle and the exhaust is getting very hot. I had to take the tc off the road because smoke is coming from the back and about to tare the engine down. Not even 500 miles later after i put her together. Any idea what could of happened? I know i did everything to spec and correctly but its the first time ive ever bored a block. I remember hearing that they have to be sleeved but i dont know anything about that. Really appreciate the help.

 

The 2AZ has cast-in iron cylinder liners but I don't know whether or not it's safe to take them out .5mm (which is about an .020" bore). That's the first thing I would confirm by reaching out to shops that regularly do 2AZ rebuilds.

Misfires and exhaust getting hot sounds like you are running lean and that could be a bad injector, so I'd likely have them flow tested.

What could have happened...well, you said, "I know i did everything to spec and correctly but it's the first time I ever bored a block." Then you you state, "I remember hearing that they have to be sleeved but i don't know anything about that."

That doesn't really sound like everything was guaranteed to have been done directly.

Who bored the block and assembled the short block, did you measure the finish on the cylinder walls and, if so, what did it come out at, what kind of pistons/rings, what bore clearance did you have on the pistons, what kind of rings and what were the ring end gaps, etc.

Given it's smoking with 500 miles on it, I can almost guarantee something wasn't done correctly.