To get my Tired Tacoma ready for our trip to the sand dunes, I needed to do a couple of general maintenance things that I've been neglecting. And after ALL OF THIS, the check engine light comes on.
I think I know what could have caused the issue. I could have either dirtied up the Mass Air Flow Sensor when I cleaned out the air box with my air compressor. Or I could have fouled up an O2 sensor when I put fuel injector treatment into my gas tank, which I've done before.
Either way, I won't know for sure until I find a engine code reader and plug it in.