By "cross-firing", I meant the spark is jumping between plug wires #4 and #8, somewhere that they are adjacent to each other. Or they are both jammed into the same piece of metal and it has damaged the insulation.

Another cause of misfires and excessive cross-fires it too large a gap on one of the plugs.... the voltage isn't quite enough for the spark to jump the wide gap on the plug, so it leaks out of the wire at some point.

The "cross-fire" is just a guess..... I agree that you should be sure the O2 sensors are BOTH working properly. They should be moving "fast".... and you can't necessarily even see all the readings if you are attempting to read the values "real time" on the computer screen.... you need to do a "log" so you can look at the sensors over a longer period of time, and see each of the samples.

You have to understand the nature of "closed loop"... the injector fires and adds fuel, combustion takes place, the burnt gasses exit the exhaust and pass the O2 sensor. The sensor sees (for example) "lean", and tells the PCM. The PCM richens up the next injector pulse. Typically, the pulses swap back and forth from rich-lean-rich-lean.... and I'm pretty sure they do that on purpose. Remember... the stock sensors are intended to measure the exact 14.7:1 A/F ratio that the engine needs for minimum combined emissions. So.... even though the O2 sensor mV's seems to be swinging over a wide range, most of that range only represents A/F ratios in the range of maybe 14.6:1 to 14.8:1. At 14.7:1 very tiny changes in A/F ratio produce a very large change in O2 sensor mV's.

That is the nature of "closed loop".... fire the injector, read the sensor, correct the next injector pulse based on the sensor reading. The stock PCM is fast enough to do that about 9 times per second for each bank of the engine. My MoTec does it up to 200 times per second for each cylinder.

 

yup. thats what I figured afered converting both of them to KPA and running that into the formula and coming up with 19 inchs of vacuum.







let us know what you find man.

 

I did actually do that last night. The readings that are in this post were taken from a log. The data you see was one line item I picked all the way across all the parameters on the spreadsheet. So, the data that you see is what every reading was saying at that particular time.
Now that I didn't know. That's really interesting. No wonder the slightest malfunction whether it be an O2 sensor, injector, etc. could make such an impact on how the car runs.

HBHracing -
Thanks for the trying on those calculations. I appreciate the effort.
I will keep you guys posted on what happens. You guys rock.

 

You would most likely know if you had injectors/plug wires crossed. I have done it on multiple occaisions and most normally will not even be able to get the car to start and run (referring to plug wires that is).

I would definitely agree that replacing your O2 sensor would be a good first step as it doesn't seem to be acting right.