You can describe your findings all day long and people can guess all day long, but until we know EXACTLY where the noise is coming from, no one can give you the correct answer, I am sorry. If you know anyone who has a stethoscope, borrow it from them, if you cannot afford one, you cannot afford the repairs or to throw the "solutions" people give you at it, and should probably re-examine your priorities if you need this vehicle. You need a stethoscope and a mechanical oil pressure gauge to get much of a meaningful diagnosis. A compression gauge may also be handy. Any other diagnosis will be through visual inspections. Pull your plugs and look down into the cylinders and at the plugs for any obvious signs, look at your exhaust manifold for cracks, pull your starter off and crank your engine over by hand (battery disconnected) so you can look for cracks in the flex plate and visually inspect the rest of your engine. Pull your MAF sensor off, if you have a multimeter you can test it, but, you can give it a visual inspection too, then see if the elements are shorted or broken.
Since when does a 1st gen have an inspection cover for the flex plate? All the first gen transmissions I have seen, the only way to access the flex plate with it attached to the engine is to take off the starter.
