What is the proper tightening torque for a 1991 Toyota pickup oil drain plug?

The proper torque for a 1991 Toyota pickup oil drain plug is 20-25 ft-lbs (27-34 Nm). However, always check your owner's manual for the most accurate and up-to-date information specific to your truck's engine. If you don't have the manual, a reputable Toyota repair manual or online resource might provide this information. Over-tightening can strip the threads, while under-tightening can lead to leaks. Using a torque wrench is highly recommended.