1G Cold Start idle surge

[all black 4G63]

hello, I have a 93 GSX 67,000 miles, it is stock except for an old HKS vein pressure controller (SD) system. When the car is cold soaked the idle surges bad and almost stalls. However, when the engine warms up the surge disappears and everything is normal.
The first thing I did was remove the old HKS VPC and reverted everything back to stock MAF. The vehicle idled worst a did not smoothen out well even when warm. At this point I checked and replaced the plugs and wires. The plugs were black and the wires did not match. However, this did not change anything. So I tested the ECT resistance cold. I was measuring about 2.6K ohms and there was 4.7V on my signal and ground KOEO. The resistance matched a brand new ECT sensor that i have.
At this point I can't determine if the FICV or ISC valve would cause this or both, or if I am heading in the wrong direction?

Thank you for any input!

 

[ThunderChild]

FIAV, very common issue on these cars. Personally I keep mine, and ended up screwing the FIAV plunger in some to make my idle surge go away on a couple cars. There is no spec for this unfortunately, and it requires removal and reinstall of a core plug on the back of the FIAV. The other option is to delete the FIAV and hold the throttle for the first minute or so in cold starts.

 

[all black 4G63]

thank you. Is the FICV not available anywhere these days?

 

[all black 4G63]

FICV MD614454 found it.

 

[ThunderChild]

I was looking for you but got sidetracked haha. A new one should be a bolt on affair.

 

[all black 4G63]

thanks man! ill follow up once i install it.