The good news is that testing a misfire code, or misfire codes, or a rough idle condition is not that hard and it's something you can do! In this tutorial, I'm going to explain in some detail the most common causes of misfires and misfire codes (P0300, P0301, P0302, P0303, P0304 -OBD II equipped 1.8L Toyota).
Solder flux is a type of metallurgy component used when soldering two metals together. The flux is an inert substance that prevents the formation of metal oxides at extreme temperatures.
It's actually hollow, and inside there's a central core of flux. Then as you feed the solder into your workpiece, the flux then distributes itself over the surface of the work, and does its action in reducing those metal oxides, preventing them from occurring as you're doing the soldering.