RPM Hunting Season!!

[SlayZombi]

Ok, so got a fun one today. So lately my 2001 Saturn SL has been acting up on cold starts. And yes ONLY cold starts. When I go to start it up, the RPMs will be in the normal 1200-1300RPM range but then swing up wildly to 1700, before plunging down to about 400. This cycle will continue although it tends to spend more time in the low RPM range rather than the high range. If you try to shift it into gear it'll either stall or if you manage to actually get it going, it will buck like a bull. Give it about 5 minutes though in this state, and the RPMs will return back to normal with no driveability issues whatsoever. On a hot or even "mild" start, this issue is not present.

I know you are all thinking ECTS, but I changed that when I first got the car in 2018 to a brass-tip version and soldered the wiring correctly. Also, the EGR valve has been cleaned twice in my ownership, the throttle body was cleaned when I first got it, and the IAC valve was also replaced when I first got it. Thinking it may be that common issue with the intake gasket.... thoughts?

[me.theuser]

well I suppose it could be the maniifold gasket and then it warms up

I diagnosed mine by spraying starting fluid over each port

how about the TPS maybe on its way out?

just a WAG
you might look for a vacuum solenoid that has a leak after the valve
maybe it supplies enough vacuum to do the required task so no engine light but leaks to atmosphere causing the engine to run bad till warm up (AIR system solenoid?)