misfirea at idle...

[Stez]

I have a very weird behavior of my O2 sensor:
at idle (not stable, may be because of this problem?) it has regular spikes down to 0 and up to 0,8.... I have the same spice occur when pressing the throttle pedal but during part throttle there is no such spikes, it looks pretty constant, but after the hard engine rev in the moment of letting off the pedal i got a spike again.
What does it all means????
Misfiring problem??? i have installed new plugs ngk bpr7 and the wires are pretty new too (less than 5k miles), maybe something wrong with coils? (the O2 sensor is generally new too)

 

[larsrya8]

I assume by "spikes" you mean that it isn't drawing the steady sine curve that it usually would? A very "spikey" O2 signal at idle usually means that your injectors aren't matched very well... at least one of the injectors is injecting a different amount of fuel than the others.

See if you can tell by looking at your spark plugs. If one is showing the mixture being off, you've found your injector. Of course, this will only work if the mixture is really off.

 

[Stez]

Yes, by spikes i meant that the curve is not steady!
You think it can be something wrong with injectors??? may be the injectors wiring is bad? because i had a few time an engine light failure occure, that was injectors code, after i toutched the #1 injector wiring - the code is disappeared. Im actually already thought about changing of it - so can it be a real cause of that behavior, or it could be something other??

 

[Ultimatedsm]

If your O2 signal is not steady, it is more likely your O2 sensor. Did you gap your plugs correctled?

 

[Stez]

my plugs gap is 0,7 mm, as for O2 sensor - its really new, and furthermore its pretty steady during acceleration and steady cruising, this is unsteady only without load (at idle) and than press or depress the TPS