Ok guys. Once again I am back with another problem. My car is making a sound that I can only describe as "a non-rhythmic rattling" under acceleration. The sound is a bunch of sharp pops almost like there are marbles in the engine or something is hitting something else. The harder I push it, the worse it gets. It is only doing this under acceleration and not sitting still. It does it worse in high gear at low speed and I go anywhere past 1/2 throttle. It is also worse when I run low octane fuel. Running 93 octane helps tremendously but does not alleviate the problem. It only does it when the engine is under load. I can slowly run all the way to redline without this noise occuring, and I cant reproduce the sound sitting still. I was told by a member here that my car should run fine on 87 octane and I agree. Its a 95 GT 5.0 with stock internals. BBK intake and magnaflow catback. Nearly stock. Any ideas?