A little while back it was mentioned on here that a mechanic solved high HC on a emissions test by using some kind of black stuff around the intake hose where it connects to the throttle body.

I found that there is a sheet of gasket material sold at most chain stores. I cut an inch wide piece off the end of the sheet I bought and wrapped it around the throttle body to measure the cut. The stuff will rip if your not careful but I got a good piece made. Had no problem getting the intake hose (used original volvo cleaned with degreaser and rag) to fit over the gasket material. My car has performed with a much softer pedal on accelerations meaning it has more power. The idle which had been low and erratic has now stabilized except when I first start the car in the morning. It won't die now but it struggles the first bit. Thinking maybe I need to change the filter on in-tank pump since my main filter has been replaced multiple times due to either rust or a build up of dust like from a dirt road in the tank.

Anyways, a sheet of the gasket maker is about $6 but its an item I plan to use every time I take off the intake hose. Enough material for at least 12 self made "gaskets".