On our 6509, we have a x6516-GE-TX card with 2 ports that aren't working. I've reset the ports to their default values and matched the config to other 'good' ports. The only thing I've noticed that's different on the 'bad' ports are some 'pkts dropped from output queue' [OQD's] when I do a show int summary. Not sure if this is the problem or not.
The end client for this port is a standard PC with a gigabit nic, nothing special. Works fine if plugged into other switch ports.
Please let me know what other troubleshoot options I could perform.