Rough running

[Locost_builder]

Hello everybody,
Since my project is now out of winter hibernation, I'm trying to address a persisting problem with rough running and backfiring at steady state highway speed (about 3200 RPM). Details are:
Car - Locost 7 homebuilt, Toyota AGE powertrain (donor 1986 Corolla GTS). Engine has been overhauled, blueprinted, and moderately massaged with cam profile upgrade, 9:1 compression, and upgraded internals, induction via the Toyota TVIS system, exhaust via headers and a side pipe with a straight through glass pack. The wideband O2 sensor is about 24" from the valves and 36" from the exhaust outlet.
Megasquirt built from a kit with MSII 3.0 board, 3.4.1 firmware, direct coil control with dual coils, wasted spark ignition from a double-decker board with two BIP373 coil drivers, independent baro sensor, FIDL controls TVIS, IAC1 controls radiator fan.
I'm using Tuner Studio MS version 2.6.14.
The car starts OK, idles reasonably well considering the cam profile, and accelerates enthusiastically (it weighs about 1100#).
I assume I'll need to attach my current tune file and a data log, but I'm unsure which of the 9 available data logs would be most useful.
Any guidance would be appreciated.
Thanks.

[gtmdriver]

I would imagine that a data log taken when the fault occurs would be most useful.

Backfiring is usually caused by a weak mixture but without the data log I'm just guessing.

[Locost_builder]

I'm still confused whether one logger would be more likely to be useful than another. Should it be a composite, synch error, tooth, trigger, MAP, engine, engine + MAP, or more than one? Since my project doesn't use MAF, I presume I can exclude MAF and engine + MAF.
I didn't mention that I use a 36-1 tooth wheel on the crank pulley for generating a timing signal.

[grom_e30]

just a normal datalog for the moment, under the 'data logging' tab at the top of the page click 'start logging' chose where to save it drive the car in the problem area so we can see it miss behave after click 'stop' and upload that with a copy of the msq tune file. from 'file' menu click 'save tune as' decide where to save it and upload the 2 files here. if the data log is to large you can use win zip to compress it to make it smaller.

[gtmdriver]

You're in the wrong 'drop-down'.

In Tuner Studio go to the Graphing and Logging section (NOT the Diagnostic and High Speed Loggers).

Click on 'Start Logging' and it will ask you where to save the file. The default is in Data Logs in your project file in TunerStudio Projects in My Documents.

As soon as you click 'Save' it will start logging every parameter. You don't have to make any choices. Just drive the car around and duplicate the fault.

When you've finished click on 'Stop data Logging'. the log will be saved as an .msl file.

Attach this, and your .msq tune file (renamed to something other than CurrentTune) to your next reply in this post and people will be able to read your log and hopefully see what's happening.

[Locost_builder]

The stars (weather, honey do's, a friend to drive the car while I messed with the computer, grandkid sitting, etc.) finally aligned enough to do a data log this afternoon.
To refresh - Locost 7 homebuilt, Toyota 4AGE engine with (about) Stage 1 cam upgrade, TVIS induction with 280cc injectors.
MSII 3.0 board kit with Version 3.4.1 firmware, Direct coil control/wasted spark ignition via double decker board with two BIP373 coil drivers, independent baro sensor, Innovate Motorsports wideband O2 sensor.
Tuner Studio MS V. 2.6.14
Tune derived from one posted on a Toyota 4AGE forum slightly tweaked by the "that looks about right" method.
Data logs from a 3 mile drive on a local highway (8000' elevation).
I just purchased Megalog Viewer, but still can't figure out what all the data means.
Thanks for any help.

[grom_e30]

you may want to look at your grounding as your signals are pretty noisy. afr reading goes funny battery voltage hits 21v, and you appear to be way to rich at cruise ego corrections is pulling out like 40% of the fuel out