on those cowl plugs, i kept having issues, finally just left them both out, that was 3 yrs ago now, checked several times since, not found a single bit of debris...with the rubber 'lip' around the hole, mine were clogging in as little as 3 months from these big darn pines we have along the drive- without the lip of that plug, they rinse themselves out- also, if you have buildup in the cowl drains, suggest looking at bottom of fenders with door open- leaves build up back under there too.
the other areas on mine that were water problems:
heres a pic of the cheep cowl plugs- there are ten of them
removing the drivers side requires pulling the wiper arms- ive got a 'glass hood, kinda thick, not a lot of room for a puller- used my imperial eastman flaring tool, *just* fit in there-
heres what the factory 'seals' look like- all ten were loose, flared out at the center allowing water in...threw them away.
heres a few of them glued in- used 'automotive goop' clear adhesive /sealant- been sold on this stuff for a long time, since 20 yrs ago in the rc airplane/heli hobby... dries fast, kinda rubbery, sticks to about anything- its real 'stringy' though, gotta be careful...it flows out as it dries, great stuff
heres the other spot that failed on my 06- the 'gaskets' around the window frame were oozing around the mirrors- the plastic just pops off, and the 'gasket was trashed on both sides
I got some closed cell self adhesive 1/4" x 1/8 weatherstrip and replaced it
this was a couple years ago, havent had any issues since- and due to to many cars, this poor thing sits out every day all year, even buried in snow hibernating for the winter(still hasnt seen salt)