I have replaced everything on the car...opti,wires, plugs and coil......and I still have a miss at the top of my gear...around 6k.....I had my car dynoed and it was dropping 50 hp when it would miss......then it just picks right back up and carries on.....It couldn't be valve problems because it wouldn't pick up so fast if it was....someone told me that.....but would running lean make it missfire.....it got up to 15 on the a\f.....and it is suppose to stay around 12 right?

 

Well, getting 15:1 AFR at the dyno shop, they should have stopped dyno testing your car. That is very lean.

Are you getting any false knock at that RPM?

Could you possibly be taking it to high up and getting vavle float? Maybe your simply out of power??

But until you get that lean condition worked out, I would really take a look at your fuel system, vaccum leaks, etc...

Good luck.