So I got a 95 GSX with minor mods. The most extensive engine mods are UICP, 1G BOV, LICP, MBC, Intake Pipe and K&N conical Filter.

History:
1 year ago got idle surge bad. Replaced the ICS wwith a used one. Ran fine. Then started acting up again two months ago. Bit the bullet and took it to the Mitsu dealer. They told me ICS. But wanted $400 to fix it. Sorry I've owned my GSX long enough to know how to change a ICS. Anyway I got a brand spankin New ICS. Put it in and my car idles at 750-800RPM.

Problem:
Now when I start it and drive all is well. But if I turn it off and get back into it then we have it surging to 1500rpms. If I hit the gas and bring it up to 4500 RPM quick it will then drop back to 750-800 RPM. Then it will start again. It seems to only happen if I've driven it for awhile and then turn it off and shortly hop back in it again. I would estimate the time to be about as long as it takes to fill the tank at the Gas station.

What I've Found:
when it is surging I have popped the hood and then inspect the Throttle cable. IT's not super tight and also not super loose. But I can actually put my thumb on the assy that the Throttle cable attaches to and push it closed. The idle then drops to 750-800RPM's and all seems well. But it will come back in a bit.

Questions:
What can it be?
Dirty throttle body, when it heats up there is some sludge or gunk in there that blocks the Butterfly? That is what I am assuming.
PVC valve going bad?

Any ideas would be greatly appreciated

Thanks

clean the throttle body, wd40 that bitch. see what happens.

When I got my talon 2 years ago, it was doing almost the same thing. I ended up blocking off the fast idle air valve on the throttle body and re-routing the coolant lines. It seemed to solve the problem for me, plus it kept the throttle body a bit cooler.
Good luck.

i also blocked off the FIAV and ISC with a plate that fellow member Jet made for me. my idle used to bounce around everywhere, and now its just fine.

I'll check on what you suggested and see if that helps. Thanks.

Use carb cleaner on the TB instead of WD40.

Anyone knows where I can get a cheap fiav? I have the same problems and I've done everything
I cleaned the tb wd40 plus the carbcleaner. I'm getting the biss screw and trying the fiav if that'll help.