Started the car up and when i hit the gas you can hear a knocking sound. Any ideas of what that is? I have heard rod bearings. How do I change/check those?? Can I do it myself?? Please help.

 

Try singling out the noise to a cylinder.

 

if you find out it is the rod bearings, which it very well could be, yes, if you know some about cars you can do it yourself.. drain oil, drop pan, remove connecting rod, drop the piston, and your rod bearings will either fall off, be stuck on the crank journals and need taken off, or be on the connecting rod..