The 1st gen eclipse "BOV" is really a by-pass valve. They are metal and considered an upgrade for the 2nd gens. Has it been "crushed"? Normally they bypass the air back into the intake just before the turbo, when the throttle plates are shut to prevent compressor surge. This is good for a car using metered air, since you don´t loose any air. If the valve has been crushed (you DSM buddy should know) then it is setup to vent the air into the atmosphere and make the cool pssshhh noise we all love. With a metered air car like the escort, this will cause you to run rich for a split second after the shift since the computer thinks there is a certain amount of air going into the engine when in reality it is blown out into the atmosphere. On my mazda I use a Apexi BOV vented into the atmosphere. It is a metered air car as well but I don´t have any driveability trouble at all. If the DSM valve isn´t crushed, then you need to vent it back into the intake. Otherwise your car will not idle. I could probably write a book on this stuff so if you need any other info, just ask. The 1st gen valve is a good valve for the money since it is so cheap. An aftermarket valve will run you $200 or so plus the welding to get the flange. Making the DSM valve work with your aplication should be relatively easy since they are really a universal item.