What can cause a missfire? Plugs? Wires? Opti? Coil?

Anything else(if even all of those can?)

 

Plugs, Wires, Coil Wire, Coil, Opti, Bad O2, Failing Injector, many other things.

Post more about what is wrong with the car. Does it go away at WOT? This would help indicate if it is mechanical or sensor related.

 

The reason im asking about missfire is because the left o2 is running lean. I read that missfires can cause a lean condition because of the unburned fuel, leading the O2 to read more oxygen per fuel and run lean.

Ehh its in this thread http://web.camaross.com/forums/showthread.php?t=454778

ill copy and paste it though..

"So this is a problem ive had for a few YEARS now. I never drive the car too much, cause I ride the bike everywhere.

The car is throwing a Code 44 = Left o2 sensor running lean.

Changed both O2's and switched them, same code....

This means something is causing my O2 to run lean, such as a vacuum leak before the o2, correct?

I replaced the left(driver) side header gasket twice, no change. Ive taken off the intake and redone the gasket once, no change.

Where else could I be getting a vacuum leak on there? I dont know how to check vacuum, other than visually inspecting the hoses on that side(which I have).

I do have an LT1 Scanmaster, and have looked at all the numbers. From the page that tells you what they mean, I have gotten that there IS a possible vacuum leak, due to my IAC numbers being much lower than normal.

"At idle, you should see roughly "20" to "40" (this is fomr my M6, idling at 800rpm). And, it should be steady. Any lower and you probably have a vacuum leak, or the throttle return stop screw on the throttle body is preventing the blades from fully closing." ----Mine are around 9 at idle.

Coil and opti were changed, no improvement. Also I have replaced plugs and wires a while ago...still persists.

Car runs rough on start up, then calms down once the engine gets to like 170*...then once its hot(such as sitting in traffic) the RPS drop, oil pressure drops, and it starts to run really rough. RPMS drop to like 550. Ive also taken out the TB and cleaned it all out. I cleaned the IAC, but it looked pretty coated in crap.

Change IAC next or look for vacuum leak?"

 

Hmmm, I would spray everything down with brake clean searching for vacuum leak.

If theres nothing, then the IAC is worth checking. Are you sure theres not something wrong in the wiring going to the O2 on that bank?

Try unbolting the fuel rails and cranking the motor. Make sure all 8 injectors are spraying a nice "cone" shape

 

hmm never thought about taking the fuel rails off and doing that.

as far as wiring, im assuming the wiring is good because it doesnt look cut or burned or anything, but im not really sure how I could test them. The driver side o2 wiring harness has no give in it and it barely has enough play in it to hook up to the sensor.

 

To test it, you could probe on end by the sensor/injector/whatever, and other end by where it plugs into the PCM. Check the resistance. If it is a broken connection, there will be no resistance, no continueity. If there is, there is a connection from the sensor all the way to the PCM.