Bad idlers,

My rough idle is reduced by 70 percent after replacing a worn out check/non-return valve (a one way valve). Thanks to Matt (AKA On the ball!) on this board.

Dealer would love to fix this since vacuum problems are hard to pin point. However, who has been replacing all kinds of other parts should try replacing this. It is amazing how this simple $20 valve (Dealer item: Swedish Engineering: 800-928-6586) can reduce major annoyance.

Part number: 9135666

Part description: This valve is the size of 5 or 7 stacked quarters but a bit wider in diameter. Half of it is black and other half is of white plastic.

Location: The valve goes to the IAC valve connection (Bay13 calls it ‘Vacuum tower’) via hard white plastic hose. The other end connects to a tee. One end of this tee goes to the VIS (whatever that is?#@) solenoid valve (near the air filter box) and the other end to the vacuum reservoir (next to the driver side bumper and behind the fog light).

In plain English find the white hard plastic thin vacuum cable on the driver side, between the engine and the cooling fan that has a tee connected to it. The black and white valve is connected to the tee.

Accessibility: Remove the air intake to the air-filter.

Ronjon
'93 850 (123k miles)