Happens to me but only when I have shoes on and press too hard...therefore , I usually sew barefooted.
I am looking for a Janome Magbolia 4500 just because I tried one at retreat and love that it can be adjusted to go slow no matter how hard the foot presses......With my vision, this will be helpful....Too fast for my eye to keep up sometimes....
At least no one discovered ghostly occurences in those feet. LOL.

I have not had that happen. When I get up from the machine I turn it off so one of my four cats will not step on the pedal.

I know. It is possessed. I got up to iron and the machine was running by itself. Then I pressed the footpedal and nothing happened and when I took my foot off it too off goibng a mile a minute.

No really your foot pedal is probably bad. That is exactly what happened to mine last month.

That is my machine exactly as you have described above. I am also of the opinion that it is the computer as I have tried using my machine in different rooms and that has made a difference - tv on/off, radio on/off, computer on/off also makes a difference depending on the time of day or direction of the appliance. :confused:

I now only use the foot pedal to wind the bobbin then I remove it and only use the stop/start button for all my sewing.

Yes, my machine used to do this. It didn't matter if I used the foot pedal or the start/stop button. It would just go and go....at a slow speed, but the only way to turn it off was to turn the machine off! It was still under warranty, so the repairman replaced the mother board. I haven't had any problems since!

Thanks for all your suggestions....I did take the pedal apart and cleaned it all out as much as I could see....so it's been behaving since. I hope it continues to work the right way.....spending $62.00 on a foot control is not in my budget right now.....Thanks again