ok 2000 hp500 efi is idling rough sounds like on 4 cyl? also throttle is surging at idle sounds like gasping for air? I did notice plug wires look bad. Will replace them tomorrow had to order them. Any ideas? Bad sensor? Other motor running fine. Just did plugs checked cap and rotor. Im stumped

New plug wires should make a big difference, I would do that first and see how it runs.

and make sure you put them back on the correct plugs. real easy to cross 5 and 7.