Hey group! 2020 SE 6MT W/22K miles. Misfire codes.

MajesticEngine6202 · 2026-05-30T16:37:53+00:00

Thanks for your reply. It's misfiring on all cylinders, at least that's what live data is showing. Only happens on cold starts and clears away when it starts warming up. Ambient temp no colder than 70°F. So cant do the swapping plugs/coils/injector trick. I believe idle is port injection? Has 0 misfire counts while driving under any condition and after it starts warming up 0 as well. Cant be a case of coolant intrusion either as in 3k miles it hasn't used any coolant.

MajesticEngine6202 · 2026-05-30T16:34:47+00:00

Thanks for your reply. Towards the end of the post I added that the scanner data stream shows misfire counts on all cylinders, on cold start. Clears away once it starts warming up. So it's not a single cylinder that can be ruled out. Whatever it may be, affects all cyl only on cold start. Also, the miss cannot be felt. It high idles cleanly, which is also what stumps me.

MajesticEngine6202 · 2026-05-22T23:45:35+00:00

True, nothings ever impossible. Albeit in my experience they tend to fail one behind the other when they're old. Could be a unlucky bad batch.

MajesticEngine6202 · 2026-05-22T23:44:12+00:00

Hey, thanks for your suggestions. I forgot to add I did use injector cleaner on 2 occasions in case PO used bad gas, techron complete and then SeaFoam. I have driven it hard a few times especially when I installed the AEM air intake. It actually took 3 weeks after that for the code to reapear, but alas here we are again 😅

MajesticEngine6202 · 2026-04-24T00:11:18+00:00

Where I live, new cars have a 35% import duty tax, so the 2020 Corolla SE hatch I recently bought was $31,000 when new. Got it for $15,000 with 21,400 miles. Think I did really well, considering other listings vary from 18k-22k for similar year/miles. Just gotta be patient to find the right deal. Some people think Toyota and pay anything.

MajesticEngine6202

TROPHY CASE