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Gas mileage saga (I SUCK at reading logs) - who has a new idea now?

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Old 02-16-2006, 04:57 AM
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Default Gas mileage saga (I SUCK at reading logs) - who has a new idea now?

<a href="https://forums.audiworld.com/s4/msgs/2263117.phtml">post 1</a>
<a href="https://forums.audiworld.com/s4/msgs/2262916.phtml">post 2</a>

All right guys, I OFFICIALLY suck at reading logs. I promise to never read them when I'm tired again. So, the car is not leaning out at WOT like I thought. It leans out when I let off the throttle. *smacks head* Duh, Joel.
So, I'm back to square one. I really don't know what's up with the car. My O2 and cat readiness codes are still in the red, so I need to know what to look at with regards to those.
A couple of other things. At the ATL dyno day, I logged 003 and 115, and my engine load % dropped from 133% at 4600 rpm down to 82% at 6800 rpm. Interestingly enough, the dyno tail sniffer said I was running lean. WTF? This was right after my EGTs were replaced, so here's my question: are the new EGTs set up to run you richer and also limit power? In the end, that's the only thing different from before to now. (I'd heard some rumor about that but was never able to confirm it.) What would cause the O2 and cat readiness codes to not be in the green?
Any help at all would be appreciated.
Old 02-16-2006, 06:45 AM
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Default Obviously there are many things that can affect your gas mileage. It seems like you covered most...

Tire inflation = ok
Climate = assumed ok i.e. no sudden changes
Lead foot = You said you have been going very gentle on the go fast pedal.
Gas type = (Any changes? Bad gas?)

Let me start with it is amazing you get over 400 miles/tank with this car. 350 would be very very good. You must live on a highway ramp, and never do any driving around town. How much fuel do you usually get at a fillup?

You say that your O2, and CAT readiness codes never seem to pass, but you do not get any DTCs. How long do you drive the car before checking the readiness codes? I know the CAT/O2 readiness codes have a pretty specific procedure to run before they pass. I believe the engine has to be run at 1900-2200 RPM for 60 seconds or something like that.

Do you have any rotten egg smell coming form your car. This would possibly point toward a failing CAT, which also might not throw a DTC. Another idea might be that your O2 sensors are ok, but the wiring is a little flaky.

Hopefully you figure out what the problem is, I have all three posts tracked, as I am interested to see what your final resolution is.

Good luck.
Old 02-16-2006, 07:23 AM
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Default Answers inside.

I get my gas from Shell about 90% of the time, and this means before and after the problem. Yeah, I drive 40 miles one way to work at 65 mph (I set the cruise), so I would usually go to about 350 and fill up with a little under 13 gallons.
I have driven all the way back from Atlanta to Nashville and then back and forth to work and never gotten them to pass lately. Going to get the test procedure and run them today.
No rotten egg smell, but I have a bad smeller anyway, so I probably wouldn't notice. However, everyone else would, and they'd tell me.
I hope it's not flaky wiring for the O2's, since they've been doing good for so long.
More to come, hopefully. Thanks for the support!
Old 01-19-2009, 08:44 AM
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FYI, the final answer ended up being the Revo trial software. It screwed up the car.
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