If the 4 barrel kicking in makes the lifters sound like they're rattling I would suspect a pinging / pre-ignition issue.
If a lifter / rocker is rattling constantly it's more likely a stuck lifter than a loosened adjustment nut.
96 T/A, Black/Graphite Leather, T-Tops, 6 speed, 10 speaker Delco/Bose "Monsoon"
Original owner, 191k miles and counting.
Total engine rebuild at 187,020 miles.
AIR delete. Bored .030 over.
Comp cams Xtreme Energy LT1 266HR-14 street cam and springs..
Last edited by NavyVet; 07-12-2013 at 06:55 PM.
Reason: dyslexic keyboard