Another thing....pull your plugs out and look at them just after driving it, and the problem orrurs......especially look at the electrode and the anode, and also the insulator and post up what it looks like.....color, amber, yellow, dk brown, light orange, red orange, ashy grey, black and sutty, white and ashy, black and greasy.....etc, just by pulling the plugs out and comparing each other b/t the 4, and looking at the plug in general, can tell you alot about whats going on in the combustion chamber....also is the problem in any way associated with being hot cold, warm, ran for a long period, after idling for a long period....what is your timing set at?
