97PFTA

So since I bought my car I have had a misfire that seems to be primarily in cylinder 7, but every so often I get a p0300 code as well. 99% of the time it is a p0307 though. I have no other issues with the car. The AIR system and EGR system had vacuum hoses mixed up so I was having those codes at first, but i rerouted them properly and no more codes.

The misfire seems to happen most when the car is around temp, and in a closed loop. Sometimes it happens when it’s in an open loop, but not often. I started watching the sensors and noticed that the voltage on one of my 02 sensors jumps around sporadically, two run negative, and one runs consistently around 12V.

I know literally nothing about what they are supposed to signal and what voltage they should be at. I recorded some of the data this morning, and was hoping someone could tell me if maybe my 02 sensors are jacked up.

StealthFormula

iTrader: (35)

I personally don't know what the readings should or should not say or what they mean but I'll add this. I had a sporatic misfire that I dealt with for several years. It seemed to occur from the open to closed loop transition. I couldn't figure it out and didn't always have a code show up for it. Thinking it was 02s I replaced them along the way with new OEM ones. I have long tubes and the issue finally went away once I converted my front 02s to C5 Corvette ones which apparently have stronger heaters in them. If you have long tubes, just something to think about. Not sure if it's your issue but throwing it out there.

AdsoYo

iTrader: (1)

Haven't seen that scanner program before but if it's able to make a graph or excel sheet that would be more helpful since O2 millivolts are constantly changing. The screenshots you posted show O2 millivolts at values that are normal.

Something like this would make it easier to see if the O2's are working properly: