I have a 1998 dodge intrepid with a 2.7 engine. When i first start the car its fine but as soon as it warms up it starts knocking. And i am not sure what is wrong with it.

You should check your engine oil pressure and see if it is within the spec. Pull the oil pressure sender under RH exhaust manifold (passenger) and screw in a guage and see what it reads. Should see like 60 psi. Also look in the oil filler cap hole and see if you have a milkshake in the oil.