Misfire detected only on stock tune.

[Oxyg3n]

So, I've been on an OFT tune for awhile and just swapped my stock headers back onto the car. So I went ahead and flashed the stock tune back on the car, and here's the kicker, I had e85 in the gas tank and tried to start the car with the stock tune. The car started, but quickly died. (I know this was stupid, but it's already happened and I've since filled up with 91)

My live readings are now showing misfires on cylinder 2 and adv. multplier of 0 with the stock tune. Now, I went ahead and flashed back to a 91 octane OFT tune, and misfire readings are all back to zero and everything else normal.

So I went ahead and flashed the stock tune again, but the car still has the misfire readings and 0 adv multplier in its memory. Started her up, and still, the same issues. Don't really hear anything wrong though. Would I have corrupted my stock tune file or something when the car died instantly after the flash, not letting it "learn" for a minute like the tablet instructs after flashing? I'm not sure why it's only misfiring when on the stock tune and not the OFT one? Any feedback would be much appreciated.

Stock Tune:
[IMG][/IMG]

OFT 91 Octane Tune:
[IMG][/IMG]

[sly]

Is there anything else non-stock on the car? Your fuel trims on stock are showing a correction where the 91 tune is closer to 0. So something is causing your trims to adjust one the stock tune, indicating that something on the engine is not behaving stock. If this is at idle, you engine vacuum is also higher with the 91 tune, indicating that that tune is more what your engine is wanting...

[Oxyg3n]

Originally Posted by sly

Is there anything else non-stock on the car? Your fuel trims on stock are showing a correction where the 91 tune is closer to 0. So something is causing your trims to adjust one the stock tune, indicating that something on the engine is not behaving stock. If this is at idle, you engine vacuum is also higher with the 91 tune, indicating that that tune is more what your engine is wanting...

I find that the fuel trims could fluctuate a bit. I just swapped back to my stock headers, so everything is stock other than my Perrin catback. When I got my stock headers removed, the installer did say one of the OE sensors felt seized when he tried to remove it. Would a leak at the sensor cause misfires?

My theory is that the stock tune read misfires when I tried to startup the car with stock tune + e85 in the tank, and now it's in the memory and I don't know how to reset it.

[sly]

Simplest way to reset the memory, if you don't have a scan tool, is to disconnect the battery for 15 minutes and then re-connect. If the O2 is leaking, it could make the system overly rich by possibly pulling in extra air. The ecu would see this as lean and then try to richen up the mixture, possibly to the point of misfire. But I would start simple first and try to clear out ecu memory by disconnecting the battery.

[Oxyg3n]

Originally Posted by sly

Simplest way to reset the memory, if you don't have a scan tool, is to disconnect the battery for 15 minutes and then re-connect. If the O2 is leaking, it could make the system overly rich by possibly pulling in extra air. The ecu would see this as lean and then try to richen up the mixture, possibly to the point of misfire. But I would start simple first and try to clear out ecu memory by disconnecting the battery.

But that would show misfires on the oft stage 1 91 tune too right? I actually disconnected both my neg/pos terminals for 45 minutes before I flashed to the oft tune to see if there are any misfires which there weren't. But when I flashed back to stock again, the previous misfire readings were still on the car.

This is the confusing part, because to my understanding every time you "erase flash memory" and write a new tune, everything should start from scratch. So this is causing me to believe something may be corrupted with my stock file?