I'm experiencing a problem I have never encountered.
The background info: I ported my TB some months back but I got into the idle control area due to my over aggressiveness. No big deal, I just lived with the slight idle surge and allowed the ECM to pull a little extra timing to try and control it. I finally picked up another TB and decided it was a good time to scale my tune. Now, I am experiencing and off-idle surge of about 200 RPM. The scanner shows and idle ETC% of about 10%. Now at frame 1280 in the attached log, you can see I give it a little throttle and hold it, just enough to bring it off idle, and it revs up just short of 1300 rpms. Then the weird shit starts. Without lifting off of the pedal, the etc% drops to 6% and the idle drops as low as 480rpms. It stays this way until either I increase the throttle or completely lift off. If I lift, the throttle slowly returns to normal. If I slightly increase the throttle and hold, the rpms and ETC recover but I have as much as a 200 rpm surge.
Another symptom I have that I'm not sure is linked is the start up doesn't seem quite right either. It doesn't seem to come alive when I hit the key. It sounds very labored. It doesn't start up, rev past idle RPM, and settle back down. It just slowly climbs up to idle rpm. I have tried adding 10% to the start up airflow table with no improvement. Ran out of time to add more.
I have compared the two TBs. The original has the same part number as the new one, however, it is stamped in a different location. There are also another set of numbers that are stamped that are not the same.
Any help is appreciated. I have tried putting my old TB back on. Again, I ran out of time tonight. I have attached my pre-scaled and scaled tune, and logs with the new TB with the scaled and pre-scaled tune.