Hello All. Just wanted to post something in case anyone has a similar problem. Recently, the engine light came on in my 2001 Honda CRV (4 cylinder, 5 speed manual). I noticed a slow drop in fuel economy, from an average of 26.5, slowly down to around 21.5 over the course of about 1 month and the engine began to idle harder than normal, with a slight jump. I took it to a Honda Dealership and they told me it coded for a misfire in cycliner 1. They said it could be spark plugs, coils, or fuel injection. About 2 weeks later, the engine light began flashing when I sat at idle for about 30 seconds. I immediately called another Honda dealership and took it in. Analysis said it was actually a misfire in all 4 cylinders. Apparently there was a tech bulletin that this model had shown a tendancy to build up carbon on the head gaskets and "gunk" in the valves. This lead to the misfires and loss of fuel economy. Honda changed the spark plugs, cleaned and adjusted the valves, and performed a top end cleaning of the gaskets. Problem solved. Idle was back to normal, gas mileage was back to normal. The entire job cost about $250.
I searched this group for answers when I had the problem and found some useful information. I just wanted to help out any of you who might have this issue in the future.
Good luck.