Please be aware that Kuala Lumpur has multiple airports and that these results are for all airports serving the city.
The best day to arrive at Kuala Lumpur is Saturday and it would be best to avoid Tuesday, as prices are on average 81.62% higher than on Saturday. (Average prices, based on 202 datapoints.)
The best time to fly is at around 20. (Average prices, based on 248 datapoints.)