Cadillac Repair: cadillac, cadillac deville, auto parts store

Question
hello my problem is my 1994 cadillac deville rattles when im on the gas all i put in her is supreme gas and she leaks some oil in the front is it a place to get cheaper cadillac parts the motor is a 4.9 and one more thing what could be wrong my window on the driver side wont go all the way up it leaves a little crack that lets in rain please help.

Answer
For the pinging noise in the engine, Buy a can of TOP ENGINE CLEANER from any auto parts store and follow the directives as this will clean the carbon from the top of the pistons which causes this pinging.

As for the window, You will have to remove the inner door panel and see what is binding.