Yesterday I replaced my opti spark since it had been causing and intermitant die. After rplacing the optispark and the spark plug wire, I began to get a back fire when driving above 40 and the SES light comes on after 4-5 mins, I have nothing to test the codes and I am a broke college kid, does anyone have any idea what could be wrong?
PS all the spark plug wirees are in the correct order

 

What year LT1 - vented or unvented unit? What brand Opti did you install? Did you loc-tite the rotor screws? Are you sure you indexed the Opti correctly to the cam? Need to scan it for codes. OBD-1? - free scanning software download available. OBD-2? - scanners cost as little as $20.

You need to add a "Signature" with basic info about your car.