I have a 2007 Mustang GT, N/A, nothing extraordinary other than CMCV delete. On cold starts, ambient can be 0F up to 80F doesn't matter as long as it is a cold start, the engine RPM rises to about 1200 RPM slowly, and then ramps up to about 2100 RPM. I've tried looking for a table/setting to control this but was unable to find anything. My idle speed adder is stock for cold starts (about 380 RPM?) as are my other idle speed adders. I want to limit this to about 1200-1500 RPM max, it seems ramping it to 2000 RPM is abnormal or a bit too high. Plus, a cold start in my neighborhood seems kind of noisy in the early morning and unnecessary as I usually just chug along until I'm out of the subdivision (to let the engine warm up) before opening it up.
Any ideas on why it spikes to 2100 RPM and what setting controls this? My idle speed in drive table was 2048 RPM stock but I changed it to 1000 RPM without any effect on this. I'm also running E85 but even when it was 93 octane, it would do this on cold starts.