ABS malfunction...need advice

[67v35@valornet.com]

My '01 F250 4X4 did a strange thing today....actually, several times today. While driving at highway and inner city road speeds all of a sudden the ABS started operating without any reason. Brakes weren't applied so I'm wondering why the heck they start pulsating?? The problem seems to be intermittent and the god-awfull racket it makes is coming from the left front about under the left fender in front of the firewall. It just starts up for no known reason and you can feel the truck slightly decelerate until the ABS goes off. These episodes last maybe 5 or so seconds and then it goes away. I have applied the brakes during these epsiodes to see what would happen and the brakes work normally whether the system is engaged or not. This has really got me baffled. Anyone have any clues or have any similar problems. I did several searches and came up with nothing so far.

Thanks.