The torque on the drain plug on a 2003 Toyota Tacoma is 16 lb-ft. To ensure that you don’t damage the threads, it is important to use a calibrated torque wrench and follow the manufacturer's instructions when tightening the drain plug. If you over-tighten or under-tighten, then it could cause problems down the road with leaks or stripped threads. It is also important to inspect the condition of your drain plug before reinstalling as well as using new gaskets or washers if needed for replacement. When performing regular maintenance checks, make sure to check that all bolts are torqued properly including those around your oil pan area so there will be no surprises in future repairs and replacements.