Originally Posted by sexr3i
cam lobe could be worn to the point where its not opening the valves enough to let a the air/fuel mix in at low air speeds ie, tickover.
Above is very likely the reason. Worn cams cause missfire's and rattles just as you describe. Compression won't be effected, as the valves will still be shutting. I have worked on a lot of RST's with your problem, and it is nearly always down to the cam.