Vacuum lines and o2 sensor

[Fox Cain]

I was wondering if anyone can lead me to where I can locate my vaccume lines and o2 sensors on my '99 9-3. Got the code for the check engine light and it said misfire from o2 sensor or spark plugs. Wanted to check the other things out before I opened the direct ignition. Any other tips and suggestions are welcome. Thanks a lot for reading.

[Shazam]

There should be a diagram of the vacuum hoses on an emissions sticker in the engine compartment (on the front crossbeam right behind the grille possibly). It's like 2 inches by 3 inches, and shows the handful of hoses (4 of them I think). I think it's yellow... maybe.

[Fox Cain]

Ok so I checked all hoses because the diagram confused me. All seem to be ok. Nothing loose. So, I will check the DI friday and replace spark plugs. If it still is showing Check Engine I will start the search for the O2 sensors.

[fiveiron]

There are four vacuum hoses to check:
-Valve cover to throttle body, part of your positive crankcase ventilation system
-Bypass valve to throttle body
-Fuel pressure regulator to throttle body
-MAP sensor (by the firewall passenger side) to throttle body.

It is a very good idea to replace those with silicone hose.

Your front O2 sensor (the one that is probably causing your problem) is located after the turbo, on the exhaust. Just follow it down around the bend and you'll find it. It has a somewhat thick set of 4 wires going up to a connector sort of by the throttle body.

[Fox Cain]

Fiveiron- Thank you. I am the type of person who need it spelled out exactly like you did. Thanks a ton. I will check it all out tomorrow. Still going to change sparks friday first. Then work towards the O2's

[avid0g]

The DIC can be sensitive to loose connections onto the battery. My battery terminals had been replaced with aftermarket connectors. The cables were corroded and slightly loose inside the connectors. My misfiring error codes went away after servicing the wiring. A lot of very intermittent symptoms may be solved as well.

I have heard that Iridium alloy spark plugs may also mess up the DIC preignition detection. Since this was not designed to work with the highly pointed electrode, the plug may conduct more easily than expected when biased with a medium voltage.