seems to indicate a mixture that's too rich. This makes sense if you're engine is misfiring. Do you notice any random misfires? I'd also ask if the parts you used were OEM or after market. From what I understand, Toyotas and some other Japanese cars are finicky about parts. In the Toyotas we've had, I tended to use only OEM parts in certain applications. I bought Denso plugs and wiring as well as any part that generated a code related to a sensor. FWIW, and when I did spark plugs, I also used dialectic grease during assembly. The jury may still be out on this practice but I've always followed it as it does help get things back apart as well as help prevent corrosion that leads to arcing.
Corolla 2000 with 200k km
To deal with a code 0300, 4 spark plugs and 4 coils were replaced originally. But right after I replaced the 4 fuel injectors, a new problem arose and it would crank for 2 or 3 seconds when starting, however there's no problem when I restart within a couple of minutes. Now it occasionally reads check engine code 172 and 300. The problem persists after replacing fuel pressure regulator and MAF sensor. Is it possibly a leaked injector? (the battery is okay)
OBD data (idle)
Long term trim -28.9
Short term trim -10.4
Any input would be appreciated!