Hi folks Ive got idling issues with my03 wrx the car idle drops to about 400rpm then rises to 1100rpm the dump valve(forge) also hisses when I lift of all the time even at low rpm 1500, could the problem be the piston has stuck on the dump valve would this cause the idling issue as well ive never had any issues up to now and ive had the car 4 years

 

the spring can break inside the DV and cause issues...............

 

Hi is it easy enough to open the dump valve up to check this? Would this also cause the idling issuse?

 

yes, they simply bolt together with a few allen bolts............

 

Yep taken the dump valve off today and it was the idle spring had snapped got another spring ordered £8 so hopefully that will fix it, the fact that the spring is called the idle spring gives me confidence that this should solve the idle problem as well, thanks for the help