Honda CRX Engine Poor Mileage

Hi I Own A 1987 Honda Crx-si. I Put A K&n Cold Air Kit On It And It Ran Awesome. It Got Like 41 Mpg. Then I Decided To Put Some Plugs And...

I Have A The Notoriously Fuel Efficient First Generation Crx Has Recently Been Getting Lower And Lower Gas Mileage -- Used To Get 32mpg City...