I've had a hesitation problem with my wagon for the last 2 months.
Replaced the fuel pressure regulator, new air filter, checked the
air mass meter - fuel pump is just 4 yrs old, new fuel filter, & throttle body cleaned, and oil trap cleaned. O2 sensor is 3 yrs old. Car just passed Driveclean with flying colours... also Ran fuel inj cleaner thru 3 tanks,& using 89 Octane with 10 % methanol. (Sunoco)
Car periodically hesitates from start, I think I'm hearing a bit of backfire.
Once up past 40 km / h car runs perfectly. Idles perfectly.



Only thing I did notice was a "hooting" sound from the Idle Air Control Valve line that runs to the air filter - when I pulled the hose off you could hear a periodic "hoot".

Took the IACV off and cleaned it - BUT - is the valve body supposed to be free to float inside the casing? If you shake it should you hear anything moving inside? WHen I took the IACV off and shook it nothing happened & the valve spindle was immovable when I tried to see if it would slide back and forth ...I'm wondering if it's sticking or stuck - I would appreciate it if someone could describe how the IACV is supposed to operate & if there is a test pin on the 740 as there is on the 240 (blue connector on the right above the front wheel?).... Is there a ready source for replacements other than at Volvo in the Toronto area - ie. scrap yards, rebuilds, OEM (bosch?)

Don't hear the hooting at idle after I put the IACV back on the car now.

Are there any tests that you can do to see if the IACV is operating properly?



Thanks & Happy New Year everyone!
Dans in Toronto