Trouble Codes 1350 1375

96 seville sts

hello all.......i am having trouble once again.....
this happened today:
car running rough ,tachometer stop working ,got trouble codes above.
spark plugs are brand new however i didnt have the cash to fork over for the wires yet......could a loose battery terminal be to blame ?I recently had battery disconnected. also car runs rough ,but if i give it the gas for a few seconds in neutral it smooths out and runs fine....i had a friend install the plugs for me and he told me my wires were indeed bad.one wire was arching in the back.but what would cause the tach to not work? (battery is new)

thanks in advance