5. Multi-Meter

multi-meter

A decent multi-meter doesn’t have to be expensive. The cheapie one in the photo gets more use than the big one I spent tons of money on simply because it’s lighter, which allows me to tape it in an easy-to-read location while I’m using it. Use it to check the state of your battery (voltage), look for a short (continuity), or the condition of ignition coils (resistance).