High rpm misfire

[Silent Matt]

My '97 S1 just started falling on its face at anything over 4200 rpm at wot. It seems to be getting worse as it used to only do it a little when it was under load and over 5k rpm. Now I can hear it misfire just free reving it. It idles fine and runs great up to that point.

I've tested the stator, coil, secondary wires, and replaced the plugs. Puts out over 14v at high idle. The pickup and rotor look good(no contact and not loose). Also cleaned the carb circuits and jets. I've tried pulling the choke when it acts up but it doesn't change anything.

It seems like the coil might be breaking down or the pickup or ignition box is dying. I have a new coil on the way, just hate blindly throwing parts at it.

Anyone have any similar issues or advice?

 

[XRorXB]

Based on what you've tried already, I would be headed down the same path.

 

[XRorXB]

And how did the plugs look when you replaced them?

 

[Silent Matt]

I checked them when the problem first started and the electrodes were tan with a sooty outer ring. When I replaced them they all sooty, almost to the fouled point.

 

[Kash]

I'am having the same problem....
Any help to point me in the right direction would sure be nice.