please help
 

ok i had a code 42 after a computer tune so i repl opti plug wires and went ahead and put the njk tr6 in becouse iam trying to get it ready for the spray but the check engine light came back on with a 42 again and it would serge from 4500 to 5500 so i un pluged the msd light went out but still have the surge it does not matter wot or just slowly ecellerating it was not doing it at all till after the tune and all