DAGeekstah

HELP! I have been searching everywhere but I feel this is too specific to find the solution. History before the issue began:
I swapped my Intake Manifold from the old PGM-FI version to the 3rd generation Integra IM. While I was at it, I removed the EGR system since it was not needed with the new IM. Also changed my Injectors while I was at it. I also used the IACV that was on this IM instead of the one that was on my old IM. New gasket for IM and Throttle Body. I deleted those canisters that are against the wall that I believe re use the unburnt fuel from the charcoal canister since the new IM does not have any vacuum lines for it anyways.
So all these changes and I noticed when I would start the car, and this only happens sometimes, it would start up but then RPM would shoot down right after and stall. I found a work around I have to hold my foot on the gas when I start it so it wont die for a couple of seconds with my exhaust loud as hell since I have the Mega Power Exhaust from S2 and then idle is fine and I can drive it like normal.
What did I do wrong or what do I need to do to fix this problem it is so annoying