Check engine light?

[Zchild]

I've been having some problems with an intermittent check engine light. I followed some advice from the site and started using Top Tier gasolines and additionally added Octane boost. Since I've made this change I'm getting an intermittent engine check light. It comes on periodically, stays on a couple of days and goes out. It goes out after every fill-up and periodically on first start-up in the morning. I've taken it to several shops and the code reads that all six cylinders are miss-firing at once. I'm told that it is not possible for all spark plugs to be bad at the same time and miraculously become good or repair themselves. I had my last tune-up at 100,000K and am told that the next time I need to have my plugs changed is at my 200,000K tune-up. I'm wondering if my spark plug wires could be damaged and need to be replaced. Any help concerning this matter would be greatly appreciated. If anyone has had any of the aforementioned problems with there bimmer and could shed some light on this mystery I would love to hear about how you handled it, thanks in advanced. Happy Motoring... [driving2]