I had a mechanic do the replacement/cleaning, little too much grey hair for that now, however been dealing him for 15 years, know him well, he cleaned it twice, as much as possible without removing the intake. No 1491 as far as I know, did throw for one o2 sensor a little while ago, replaced that and it went away. My mechanic talked to contact at Honda dealer, that's where the "replace ecu next" came from.