Fed up and stuck
 

It's the usual chestnut - poor idling - Hunting, idle speed drops to low, engine stalls etc. It tends to do it when the engine is hot. I think this problem is also giving me the violent hiccuping as I let the clutch up, unless I keep the revs high by slipping the clutch.

The car has a new O2 sensor, MAF and plugs
I've thoroughly cleaned the ISCV with brake cleaner
If I unplug the MAF, the engine doesn't stall, although it runs much rougher
I can't find any inlet pipe air leaks or pipe damage
The HT leads look to be in good order.

Don't know what else to do....There are no error codes.:(

I have a Blitz dump valve. I've seen comments they can give problems. Should I change it? Perhaps I should buy a new ISCV? Bet they aren't cheap though and they might not fix the problem. Perhaps I should ditch the Pipercross induction kit and install the standard airbox (better for the MAF?).

Getting fed up with these cars. Not enjoying ownership at present. :cry:

Oh yeah, it's an STi 4 Type R.

Anyone any advice or words of encouragement?

David

If the Dump Valve is a single piston one it can give very bad idle i suggest try changing that to a standard one or one that is definatly twin-piston or that you know works fine on a Impreza.

If thats not the problem try removing the induction kit and fitting a standard air box, if this caused the MAF to break then it could have done it instantly to the new maf.

How do I know if the dump valve is a single piston?

Thanks

David

I have a blitz dump valve fitted to my m/y94 wrx. They are single piston and mine also has idleing issues. The fault is cured when the original recuiculating dump valve is fitted.