Do you mean it runs without you on it but stops when you step on? I had this, just fixed it today, the bolts holding the main wheel onto the front rotor had come out, re-attached and all good.
trevor
May 2013
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix gym/fitness equipment.