inputLayer = arcpy.GetParameter(0)
idField = arcpy.GetParameter(1)
i = arcpy.GetParameter(2) # start value
grid = r"R:GISPROJECTSDept_WaterUtilitiesToolsOceansideToolbarShapefilesGrids.shp"
field_names = [f.name for f in arcpy.ListFields(grid)]

cursor = arcpy.UpdateCursor(inputLayer)
arcpy.AddMessage("Generating ID's...n")

for row in cursor:

    #Select by location
    arcpy.SelectLayerByLocation_management('grid', 'intersect', 'inputLayer')

    for field in field_names:
        C = row.getValue("COL")
        R = row.getValue("ROW")

    for id in idField
        ID =

    Fc = str(i).zfill(2)
    Col = str(C).zfill(2)
    Row = str(R).zfill(2)
    Fno = str(i).zfill(3)
    Code = Fc + Col + Row + Fno

    row.setValue(idField, Code)
    cursor.updateRow(row)

    i += 1

arcpy.AddMessage("nnFinished...")
arcpy.AddMessage("Last ID created: " + uniqueID)