Surging idle when coasting
I need some help with a surging idle. I can't figure it out, and its driving me nuts I have gotten it better but it still is happening. It seems to happen mostly when I'm coasting down to a stop under about 30mph. Once i lift off the throttle and it is returning to idle the afr seems to bounce around.
I think the VE table is good but its odd as sometimes it will be reading a lean afr then another place in the log using the same VE cell its too rich.
Another question is what is a good timing value for idle? it seems in gear it is always going to 18 degrees, which is the value of the High Octane Spark table, but the base spark in gear table i have set to 28 (which is stock values).
Lastly, I have noticed that when i lift off the throttle sometimes it is still reading 1-2% throttle opening. Why is this? is the IAC position affect what your TPS % shows? Do i need to go adjust the throttle blade so it goes all the way closed? or is it maybe a flaky TPS sensor? cause it isn't consistent. there is slack in the cable so it should close all the way. Wondering if some how this could be causing my issue?
Attached is a screen shot of the log where it was doing it, along with my log and tune. Any and all ideas are welcome, I have been chasing this problem for a while since i got the motor back together. Specs are a 2002 camaro with single 78mm turbo. Engine is ls1 with 4" stroker, 9.7:1 cp pistons, stage 2 BTR turbo cam.
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