91' Camaro Z28 5 liter - Been having a ton of stalling, hesitating, hard start problems. Found that my fuel pressure regulator was bad and was leaking fuel out of the vacuum side directly into the plenum. Lots of gas sitting in the plenum when I took it off. A substantial amount of fuel came out of the air filter housing when I took that off also. Both filters were saturated with fuel (I replaced them and the fuel pressure regulator).

Car is behaving much better now but I found that it will not idle with the line between the throttle body and charcoal canister connected. If I disconnect the line at the canister it idles (a little high because of the vacuum leak I guess). If I slowly start covering the line with my thumb the RPMs will drop and if I cover it completely it just dies. Once the engine is warm it will stay running with my thumb over it as long as I cover it very slowly. Connecting the line to the canister is the same as covering it with my thumb. I'm guessing it's fuel logged or something.

My question is, if blocking this line is causing the car to die, does that mean something is messed up in my throttle body? Is my IAC not doing it's job? I am assuming the IAC get's it's air from the filter side of the throttle body and not that line.