See the FAQ: http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F, but I would not recommend comparing the vector to find that value exactly - I'd use the min function:
data = rand(3000,2); % Sample data - replace with your own.
targetValue = 0.7636; % The desired value you hope to find.
% Get differences between actual values and desired value.
differences = abs(data(:, 2) - targetValue);
% Find the row with the closest value.
[~, row] = min(differences);
% Extract the data from that closest row.
targetTime = data(row, 1)
closestValue = data(row, 2)
