I have '98 ej20 impreza. Since cold weather came my RPM problem started again. When clutch is pressed or put into neutral RPM drops to about 100 so it almost stalls. Also, rarely when flooring accelerator it starts working on two cilinders but works normal after releasing accelerator and pressing it again.
I changed spark plugs and cables (two were bad), checked MAF and idle motor (or whatewer is called in english) but problem remains.
Any thougts on what to check next? Tnx

 

air leaks