P2096 is being persistent. (Downstream O2 sensor)

[Cani Lupine]

If the FSM literally says throw parts at it and see if it stops, I really don't want to take my car to a dealership.

After I pull the battery to reset the ECU, the first code to show up in pending is 0421, for the cat underperforming during warm-up. That never makes it to the CEL, but 2096 quickly does, and turns the light on every time it's driven.

I wonder if that code also covers rich conditions, since that's what I'm actually seeing from the sensors, or if it's simply the wrong code getting tripped when it should be 0420.

I'll probably just go with the spark plug anti-fouler trick and call it good since the car runs fine.

[klroger]

I'll probably just go with the spark plug anti-fouler trick and call it good since the car runs fine.

Cool, I haven't heard about the "Anti-Fouler" trick to fix stuff since old worn out flathead Chryslers... but that was when Ignition Points were all the Rage... Let us know how they work on the modern stuff...

[7milesout]

I suggest you remove your RAM air stuff, and reinstall all your original intake equipment, making sure it all goes on correctly. Then clear all the codes and see what happens.

[Cani Lupine]

Alrighty, so I finally figured it out. Turns out it was an exhaust leak at the manifold gasket at Cylinder 3, which is directly in front of the upstream oxygen sensor.

I found some white specks in the manifold in the port for cylinder 3, and did a bit of research. Turns out that's caused by moisture, most commonly from a bad head gasket. But, after taking a look at the old gasket, I found the 3rd cylinder hole was sooty, while the other two weren't.

This allowed fresh air into the exhaust manifold directly into the O2 sensor, which made the ECU think the car was running lean. This caused the fuel trim to increase to compensate, making the engine actually run rich.

What's disappointing is that fixing the leak brought the fuel trim back to normal, which also eliminated the boost in power I got from running slightly rich. The long term trim is down to 0-2ish instead of 5-7.

[Basic]

MPGs should pick up a hair maybe?

Good to see you around. Been a while.

[7milesout]

But now we know what mod to make when we enter our steeds into a drag race, or road race!

Actually, I find some racing quite interesting. The guys in the northern mid-west know how to have fun. They organize these "enduro" races. It is usually some set number of laps depending on the track. So maybe 250 laps, or even 500 laps. It's long, hence the "enduro" name. A lot of times it's limited to FWD 4 cylinder cars. And they look like junkyard heaps. If there are not so many cars, in the 50 to 100 count, the racing gets quite serious. Anywho, I think a good running Mirage might be a front runner. Not for the power, but for the light weight & maneuverability. I think they'd let it compete since it only has 78 hp. Maybe 81 hp with the "Cani Lupine" mod.

[Cani Lupine]

MPGs actually did increase a little bit, since it wasn't dumping in excess fuel anymore. I'm wondering if it would be possible to add a one-way valve to allow some fresh air to get into the manifold as a cheap way to trick the sensor without needing a Dyno tune, and adjust the valve's airflow to get the desired AFR.

[skyblue]

cani, you might know, can i buy an afr gauge and wrap it around the stock signal wire for the upstream o2 sensor, i tried seeing the value in torque but i can only see the commanded value

[Cani Lupine]

Unfortunately, I'm not sure how you'd rig that up. Wiring and electronics are definitely my weak points.

I do know the UltraGauge shows the Lambda value from the upstream O2 sensor, but as for adding a separate AFR gauge, you'll probably have to look at the instructions on whichever gauge you use.