2000, 225Vmax RPM flux @ WOT

First of all I want to thank you guy for having a great support group here on www.YamahaOutboardParts.com
Here we go, At WOT on my 2000 VMax 225hp the RPM drops 300-400 and then goes back up and drops again repeatedly, it dose this thought out the throttle rage, less as you throttle down but still notable.
I have no knocking or sluggish take offs, but dose idle a little rough and cut out every once in a while. I have changed filters and replaced spark plugs. Got any ideas ?
Thanks guys!

[jb123]

clean and test o2 sensor.

http://www.boatsetup.com/O2sensor.pdf

Thanks, I'll give that a shot and post back

It was the 02 sensor, I pulled it out and man....it was just covered, to the point were you couldn't see the cut outs in the element. After soaking for a day and using a lite brush to clean it, it just wasn't salvagable, so I installed a new one and problem solved.

THANKS guys!