Are you using the stock fiero intake filter canister? Was this test performed when the car was warm? Specifically coolant temps above 180 degrees? If not then what I'm about to say may change a bit...
-O2 = high - Possible combustion problem or lean condition, likely enough to cause a misfire which increases HC dramatically. Check for exhaust leak upstream of O2 sensor, vacume leak after air metering, ect. Any source of air the MAT/MAP are not detecting. An incomplete burn of the air/fuel mix will also leave extra O2 in the exhaust.
-CO = well within range. - I do not see a rich condition based on those readings.
-CO2 is low. Indicates a combustion problem. Efficiant combustion is not taking place. When properly burned fuel and air should leave heavy amount of CO2 in the exhaust. 15% is the theoretical maximum. 12-14.5% (.12-.145 on your machine) is a good range to shoot for. Your at 9%.
-HC is really high. Possible incomplete combustion, probably causing above^^^. Possibly serious carbon buildup in the cylinders. Deffinately run a compression test. Look for high compression as a indication of heavy carbon buildup. Low compression indicates sealing problems (rings, valves, valve seals, ect.). Check ignition coil, grounds, ect as sources of deminished spark energy. I'm leaning towards a lean misfire as your underlying problem. Excess carbon buildup can cause HC to be hidden in the porus carbon, releasing it on exhaust stroke unburned. I would focus my efforts on the high HC. Once that is worked out you will find the other levels are much closer to what they should be.
-NOX is low. Indicates low combustion temps or very rich or lean condition. Most likely lean as stated above.
You CO levels do not indicate an rich condition to me. Those levels should easily pass... I think what your smelling is unburned fuel, not too much fuel. Yes, there is a difference but they smell similar.
Check all possible combustion problem sources. Your on the right track so far. Wish I would have had that equipment when I was working on mine. Having readouts of 6 gases makes diagnosing much easier.
I had 3.
EDIT: Hows your base timing? New fuel or old fuel? How did your old spark plugs look? Were they really dirty and/or worn? Any particular cylinder look worse then others?
Seeing HC in the oil fill isn't out of the ordinary. Fuel is not the only source of HC. Dirty oil and/or crankcase can also cause higher then normal levels. As long as your rings, valve seats/seals are good, and your PCV is not stuck open this should not be a problem. Since your PCV is new and you have a fresh oil/filter change you can eliminate these. You can clean the crankcase if you want. It should help a bit. Seafoam works OK. I'd look into other options for this though. I'd do this later, after you've checked compression and other sources of incomplete ignition.
If your injectors hold pressure then they are not leaking. This does not tell you how the spray pattern is though. A bad pattern could still have the injectors dripping fuel instead of atomizing it. Liquid fuel does not burn well. Check that out however you can. Also a completely clogged or not electrically working injector will hold pressure. But it will not spray fuel at all which could lead to a lean condition. If possible, you can do a power balance test. Might be easier to have then tested by a shop.
If possible, try to get a scanner on the car. Look at the O2 sensor readings, fuel intergrator/block learn values, CTS readings, MAT readings, and throttle position readings. This can really help narrow it down further. CTS and MAT can be tested for accuracy very easily with an OHM meter and thermometer. TPS should be checked through its full range. Dead spots or incorrect readings can cause many problems.
One last thing to try. Can you redo the sniffer before the cat? Possibly at the O2 bung? The CAT can sometimes mask other problems.
[This message has been edited by Fieroseverywhere (edited 06-24-2010).]
