Okay reset my ECU this morning and no codes....GREAT...took it for a drive did good until got on the highway and like usual after reseting the ecu the CEL comes on I go home....no biggie...and like usual.....its a 17 for the VSS...now I have a new VSS.....is it just a straight sensor swap.....my wiring is done right....

A6 head on d15b2 block and mpfi conversion.....or could this be related to anything like my map sensor or anything..???

 

So, this is a cable driven unit....
Follow the diagnostic procedure in the manual - with a volt meter and the front wheels off the ground, see if the ECU is getting 4 pulses per tire revolution.

 

Im assuming the speedo is still registering speed?

 

Yup just fine

 

Remove the cluster and make sure ALL the screws on the back are on and tight.

All the screws inside that circle must be there and tight.
The VSS signal goes from the cluster to the ECU.
If the speedometer works and you still get the VSS CEL then there is a problem with the wire/wiring at the ECU. Make sure the wire at B16 is there and making a good connection.