Hi there,

My 99 WRX is having problems.
When sitting idling it drops to nearly 0 Revs then bounces itself up to about 1000.
Its fine when you are driving about, Revs fine, Will still boost and be off like a shot. No problems there.

I have recently changed the MAF sensor due to it spluttering when you were putting the foot down, the new MAF have fixed that problem but the idle is not being funny.

Help me please

 

was it doing it before you changed it?
could be idle control valve

 

no it was just spluttering before it was changed which has stopped.
yeh was thinking that but wanted another opinion and to see if there was anything else i should be looking at.

 

The only other thing it could be is lambor sensor which is common to play up.
That could course it to splutter as well.
if it was mine i would put the old MAS back on and see what it does.