My ford explorer suppose to be this fast??

So I was in my explorer today which is a 4.6 litre with a v8 and decided to see what if could really do.... Wow it gets off the Lind quick , and once it hits like 4k rpms in the first gear it goes crazy.... I don't know if something was done with it before I got it but it's amazing... Also about how much does it weigh... Is it suppose to be this fast??? It's a 2002.