SO Im getting a tapping noise under load? at idle the engine of quiet and at speed it;s quiet but under load (accelerating) it gets loud especailly with the top down.. someone Mentioned that bad injectors could make that sound ?? it has a recent oil change with a heavier oil and have good oil presure ( dead middle at idle) I know ya can't really tell because its something you'd have to hear it person but I was just curious! What kind injectors should I get on a91 5.)l 140,000 minor bolt ons ( headers,throttle body,intake) also the spark plug wires are grey and have 1991 on them any chance they are the originals? any ideas on what plugs,wires caps to buy ???