AHHHH, Either I have been wrong for a while or the the termonology you are using is wrong. Either way, I will try to give my input.
The runners are actually strech of metal that connects the intake manifold and the heads. I can't think of the actual name of the plate that sit in the "secondary" intake runner. Regardless, it has a actuator on it tells it when to open and shut. It is closed at low rpm to create more torque and so the engine isn't overwhelmed with so much air it would bog. Then it opens up at a high rpm under many condtions to create more top-end. It is kinda like VTEC, however vtec does it with a Third cam lobe, Nevertheless it works off of the same pricipals.
Please, I am more of a rotary man, I am just now learning pistons, so please if I am wrong, please correct me.
To remedy this issue, it is probably a simple fix really. Is all 4 of those plates always closed or just one or two? If it is just one or two I would say the actuators themselve could be bad, or you have a bad vac job, and just replace with some silicone vac lines. Now if all plates are shut, this may be a little more hard to track down the grimlin. Check if all the these vac lines came fromt he same source, if so, check that out. It also may be an electical issue. You might have a electronic one-way chack valve, or a three way solenoid. I can't think of the actualy term on it either, man I suck today. Nevertheless, the FD has a few of these, 7-8 I do beleive and it is how it controls the twin turbo. There is a chance you have something similiar to control these plates in your runners.
Ty
[ 09. July 2005, 03:40 PM: Message edited by: 1 DIRTY 7 ]