weird rattle?

when i'm driving around there is a weird rattle coming from the engine compartment. when i put the car in park and rev the engine it doesn't do it. the noise does seem to subside when i get the oil changed. i'm i using the wrong motor oir? castrol 10/w 30 syntec? my car is a 96 gl with 102,000 miles. i see people with 150,000+ miles on their taurus. all i want is for my car to give me 2 more years, roughly another 30,000 miles. any suggestions on the which motor oil to use.

when i'm driving around there is a weird rattle coming from the engine compartment. when i put the car in park and rev the engine it doesn't do it. the noise does seem to subside when i get the oil changed. i'm i using the wrong motor oir? castrol 10/w 30 syntec? my car is a 96 gl with 102,000 miles. i see people with 150,000+ miles on their taurus. all i want is for my car to give me 2 more years, roughly another 30,000 miles. any suggestions on the which motor oil to use.
Nothing wrong with the oil you're using.

It may be the heat shield around the exhaust manifold. This appears to be a very common issue. It's not a big problem, but, of course, that only applies if that is actually what your problem is.

i had the same problem didnt worry about it cause it was running fine, when i tuned up the car n put in new plugs and wires the problem stopped, don't know exactly what it was?