OK have kind of an odd issue here.

I've had a high rpm miss for a while that usually starts around 4500-5000, it's there a little at part throttle but is more noticeable at WOT. Plugs/wires/icm/coil/opti were all changed recently so I didn't think it was any of that. I thought it might be O2 sensors so I disabled closed loop and ran open 100% of the time. At first it was still there but it went away very quickly after I did that.

So I figure the O2s are likely bad, but I thought that was odd because it was my understanding that they were not used at all at WOT. Anyone have better info on that or maybe a reason why they would affect it?

Does it act up before the car warms up? If so I dont think its o2 related. You are correct on the 02's not used at WOT. If your o2's are bad then it could possibly be fouling your plugs out rather quickly.

Not sure on that because I never rev it really high when it's cold.

I thought about that but, if the plugs were fouled wouldn't it continue to run bad? Seems like the problem went away after disabling the O2s.

Also I noticed that my gas mileage has been steadily declining over the last few weeks, which seemed like O2s to me also.

While the O2 sensors are not used to correct the A/F ratio at WOT, the long term fuel corrections, which the O2 sensors helped develop in closed loop/part throttle operation, may be used in power enrichment (PE) mode. If the PCM was adding fuel in Cell 15 as a result of the long term corrections, the PCM will use Cell 15 BLM's at WOT. So, in effect, incorrect BLM's resulting from faulty O2 sensors, can affect WOT operation. Locking it in open loop will result in the PCM using Cell 18 for the BLM's, so there would be some difference in the way the engine runs, since Cell 18 appears to be derived by weighting the BLM's in the other cells.

False O2 readings can come from faulty sensors, but they can also come from things like leaks in the exhaust before the O2 sensors and misfires. One thing I noticed, you adressed the ignition system by replacing everything - did you also check the injectors and the fuel system pressure?

If you replaced your wires recently, it might be worth a look to be sure that you haven't burnt one. About a week after I put Moroso wires in my Formy, I developed a missfire.

Turned out I was too impatient getting the wires put in place and one came loose, touched a manifold, and toasted itself. There was arcing all over the place.

Well it came back a little bit today, so it may not be O2 related. I think it might just be running a little lean. I did a log and the O2 readings at WOT were low to mid 800s. Seems kind of lean to me.

Yes SUPPOSEDLY N/a at WOT the O2's should read ~880 - 900, 920 -950 for boosted. This of course assumes they are reading correctly. I would add fuel and see if the problem goes away.

Good luck

Yeah I'm going to try that tomorrow, thanks for the help so far everyone.