Thanks for the info 440Jim. I do have the 100 amp powermaster alt, electric waterpump, and electric fan. I don't have the shielded mag pickup wires.Maybe I'll try shielding the wires before I send the box back. I was thinking the same thing about these boxes being alot more sensative then the analog boxes. I've already replaced the cap,rotor,plugs and plug wires trying to fix this problem........