Would a bad O2 sensor cause this?

[1slow95]

I changed my spark plugs and wires over the weekend because my car has been running a little rough lately. I found out that was mainly due to a spark plug wire that was barely attatched and my TPS was sitting at .50 volts at idle. Seems to be much better now.

Anyways, I noticed the plugs for 1-4 were all very black like it's running way too rich. But, the plugs for 5-8 are all dark but not nearly as black as the other plugs. I've been having a wierd pinging noise that to me sounds like it's only coming from the drivers side(5-8) of the engine. So what would cause one side of the engine to run way rich and the other side to be not so rich? My first thought is the O2 sensors, what do you guys think?

 

[95GTV8]

most likely, if i were you i'd run to autozone to see if your engine is throwing any codes. Is your CEL light on?

 

[1slow95]

Im not getting a CEL. I was told to get new O2's before I take the car to be tuned anyways, so I'll go ahead and replace them next.

 

[HISSIN50]

The CEL doesnt necessarily need to be on to have codes stored (I have even known of a stang running in FMEM with no CEL!).

So an obligatory check of codes would be good.


You can also use a meter to check the amplitude and frequency of the narrowband sweep (0.9 to 0.1 volt) to see what the thing is doing (just in case it is a wiring issue rather than the lambda itself). It's far from accurate, but it does kinda show you if the sensor (or wiring) took a total poop.

Good luck Mike.

 

[Zero Signal]

If they are stock O2's and have over 100k on them, replace them anyway.