hi 1998 uk terzo
hunts slightly when cold and warm and revs drop at junctions ect. new plugs, leads and battery fitted. also looked for air leaks but found nothing. obvious next steps are the expensive ones, maf, 02 sensor and iscv but can no longer afford to through parts at it especially at £200-£300 a go. local subaru garage very expensive and not much cop. no faults in memory so stuck on what to do. had the car for around 7 months and had this fault for around half that and spent nearly £2000 on clutch, flywheel, rocker leaks, breaks ect ect so starting to loose interest and dont want to drive it anymore. its surprising how such a little fault can really change the character of a car. any help please thanks in advance richard.

 

If the idle is too low, it will hunt, as it tries to bring the revs back up.

Try adjusting the icv a very small amount, clockwise, this should raise the idle. Mark the point where it is before you undo the 2 screws first, then if it's no different you can turn it back to where it was.

 

Sounds like a problem with the dump valve, is it the oe one? if not, it will be a vac leak somewhere