2000 Jeep Laredo won`t start

how did the starter check good? the only way to check the starter is on the vehicle with a amp meter. testing a starter off the vehicle is impossible so if thats how it was done then i would replace the starter motor. thats what is usually causing the drag of a slow crank, also make sure the battery connections are good, if i have a doubt i will cut off the ends and replace them to be sure, it only costs a few dollars because sometimes right where the battery cable meets the post is where there will be real high resistance. hope this helps