Opti Problem

Hello, I am having a misfire problem, It seems to be intermittent. I do have corrosion inside the opti connecter area. I also noticed through my scanmaster that the left side o2 was only showing 0-100 mv. the right side is showing 800-900 mv. they are not cycling at all. I thought the left side sensor was bad so i replaced it. it wasent the sensor. I also notice that the computer is removing fuel from the left side and adding fuel to the right side. My question is if the opti is not sending the proper signals will the computer over correct the fuel going to each side.


On a seperate note i noticed under the abs device on the drtivers side mounted to the frame there is what looks like a small valve with a vaccumn line attached to it. does anyone know what the valve is and where that line is supposed to go. Whoever had the car b4 me used a "T" there and it got broken so Im trying to find out if that goes to a vaccumn source.

Sounds like your sensors could be reversed or you have a wiring issue. Low voltage opti problems will not cause what you are experiencing. Both hi and low res problems will set a DTC.

You should trace the wires for the O2's from the PCM to the sensors first. If that doesn't show anything, disconnect them and see if the reading's go to 450. This will also cause the PCM to go into open loop and see if your misfire problem goes away.

If they don't go to 450 when they are disconnected, you have a wiring issue.

Since you have been experiencing fuel control issues, the plugs should be changed once you have the problem under control.

If your o2's are not cycling above and below 450mV the system will not go into closed loop.

So you're in open loop and your left bank appears to be where the problem is. The o2's read low voltage when exposed to oxygen (atmosphere). Either theres a non-firing plug or theres air leaking into the exhaust.

I would check the plugs on the drivers side, maybe your gap is too big or the ignition system isnt delivering spark (broken or shorting out plug wire?). Also look for leaks, including in the AIR system.