Are you running stock valve covers? do your valve covers have these clips/tabs? The ones on my engine probably are not the correct year for , but you should have something similar to this to clip the harness into otherwise the valve covers might not be the right ones - hopefully one of the other members can tell you for sure, or if you have aftermarket (aluminum) ones, they usually don't have any clips/tabs at all....can you post a picture of your engine?