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?

1 answer 1 comment
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.