Hi everyone,
Struggling with a cold start idle surge on a 2012 GT with a FPP twin 65mm throttle body, Cobra Jet intake, and long tube headers. Once it warms up, it idles fine. This is only for the first few minutes of start up. The engine approaches stalling after throttle is applied (blipped in my attached log). Everything seems reasonable in the data log to my eyes. I suspect that the O2 sensors may be "falsely" reading rich, and thus the PCM cuts fuel, but not sure. I don't have an external WB, so it's hard to tell. Attached is my tune file and data log. Note how the idle surges after throttle blips.
Any insight is greatly appreciated.
Wes 2012 Mustang GT Cobra Jet Headers v08 No Cats.hpt
Idle Surge 1.hpl