[Guitarman]

Simplest DIY you can do to keep your car running reliably is to learn how to change the oil and filter, and while you're at it, change the air filter each year as well (often needs no tools at all for the air filter!). This alone (annual oil and filter changes) will keep your car healthy for a long time. If you are wise enough to be driving a Toyota, that is all you will need to do most years.