Remove the oil pan by disconnecting the motor mounts, lift the engine a few inches then remove the bolts. Once the pan is off, the oil pump is easily removed with two bolts. FYI, oil pumps seldom go bad, and if they do the engine is usually destroyed before you can do much about it. If you're getting indications of low oil pressure it's probably worn main/rod bearrings. Try changing to a heavier grade oil before going to the expense and effort of an oil pump.