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I'm scanning a local's 2001 SSEi Bonneville and its got an ugly cough under light or full throttle.
Many variables take a nasty drop on the chart such as timing, injector duty, o2's, and sometimes the rpms.
The owner already replaced the front o2, coil packs, fuel regulator, and fuel filter.
Please take a look at the attached scan and let me know if this makes any sense.
Here is a sneak peak:
http://i228.photobucket.com/albums/e...uner/cough.png
Mine does this once in a while too..... don't know.
Electrical gremlins, short = poor grounds?
I wonder why you get a big shot of KR right after the coughs, mainly 2nd and 3rd...
Look how his KR is in correlation to the shift into 2nd.
Post the tune file.
Stock tune.
I'm really at a loss on this one and I used to be heavy into tuning L67's.
I would have a closer look at dampner/reluctor, crank sensor, cam sensor, and ignition module. The injectors are actually shutting off when this happens. Cam and crank sensor feed into ignition module then to the pcm.
And the ltft's are maxed out through most of log if your making changes.
The LTFTs being maxed made me think gasket leak, but then I remembered an old '94 3800 I had with a bad crank sensor doing this under uphill load.
I would be surprised if the crank sensor went on a 2001 with 50k-some miles, but you never know.