Baileys dv26 dump valve

[lurchio2]

Hi. I've recently fitted a dv26 twin piston dump valve to my t4. Most of the time it's fine. But every now and then when the revs come back down to idle they drop right off and it nearly stalls. And sometimes does stall. The majority of the time it's ok though. Any ideas? Thanks.

[scoobysn7x]

Try cleaning the idle control valve as this can cause the symtons you've mention cheap and easy DIY job there' a how to on

http://www.volvoforums.org.uk/index.php

Search for idle control cleaning in the S40 section, just a couple of screw torx bits to get the cover off, then 2 bolts to remove, disconnect it give it a good going over with carb cleaner and earbuds then refit, worth a try as s quick and easy to do, suppose it could also be an airleak somewhere, if it wasn't doing it before you fitted the dump valve check the joints around the dump valve