what are some chacteristics of a worn out or streched timing chain? does idle jump around alot? and also when im driving tachin any where between 1900-3000 rpm, every once and a while it will feel like it misses almost, kinda like it alsomt dies, that that will pass and it will be fine...i already changed plugs, wires, cap, and rotor to try and solve it..im thinkin its gotta do with the timing or ignition, whatcha guys think?

 

I would check your timing. The timing chains in mustangs are not really stretchable. They would break instead. They might give you at the most 2* of slack, but it wouldnt make it jump that bad. Are you using aftermarket ignition? ie:MSD 6AL? What about your coil?How new is it?Or It might be your ignition coil thats on the distributor, but I dont think that would be the likely cause. You sure you dont any wires loose on the plugs? what about wires that lead to your ignition coil on the Dizzy, or to the coil itself.