The video is broken. You said the RPM fluctuates by 50RPM, but do you maybe have the D-Jet "Surge"? If your idle is too high (1200RPM) you'll hit the fuel cutoff until it gets to about 700RPM or so, then it'll go back to 1200.

Combined with the "Delay" in hitting the gas, it leads me to believe maybe your aux air valve is too far open. Your mixture is too lean to get off idle. Close your idle air speed screw a bit and see if that helps.

If we could see the video I could tell if it's the D-Jet surge or not.

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2021 Charger Scat Pack Widebody "Sinabee"
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2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
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