For the past few weeks my '99 CRV was having idling issues. After warming up the idle would continuously bounce between 1000 and 1800 rpm. Also got a p0505 CEL. Tonight I decided to tackle the problem. I cleaned the intake, took off the IACV, cleaned and tested it with a 9V battery (it worked), moved on to the FITV... I backed down the screw mechanism and gave it a close inspection. To my surprise I saw that the coolant line coming off the FITV was plugged with something. I poked it with a paperclip and it was soft so I worked it out. It turned out to be a 1.5" long bit of rubber that looked like it had been partially melted and then got stuck in this small space. I put everything back together, refilled coolant, relearned the idle, and now all is well!

Thought you guys might be interested in this weird find. I feel like I was lucky to find it and didn't take it to a mechanic first!

Now the question is where did it come from...?