Looks like you did not specify a Field Separator just the Output Field Separator you wanted. Sorry i don't have gawk but in Awk is this close to what you were trying to do?
Code:
awk 'BEGIN {FS = ","; OFS="\t"} data { print $1, $2, $3} /@data/ {data = 1} ' ~/Desktop/datainput.txt > ~/Desktop/test.txt
OUTPUT RETURNED:
-1.170815 0.257522 0.016416
-1.335653 0.30494 0.009793
-1.227306 0.300442 0.024001
