new maf sensor didn't fix ,same codes coming up,maf,missing cylinders... on 1999 Volkswagen Jetta

just bought car,seems to be a draw on battery upon hooking/unhooking terminal. muffler also split open..any ideas? return new mass air flow sensor?

Asked by for the 1999 Volkswagen Jetta
Run engine at night with hood up and look for secondary ignition sparks(plug wires, coil , dist cap) or you can
spray water from a bottle while idiling and see if it runs rough
I replaced the coil pack, no distributor on my model.Runs way better, still a little rough.Next will be a tune up.