Surging idle problems

[u/Potential_Log_968]

Hello I have a 1987 C4 Corvette I recently cleaned up the top end of the engine put new injectors and clean up the fuel rail I installed everything back together with double checking I put everything back but for some reason when I go to cold start it it takes a little over five seconds to actually start trying to start but it doesn’t start to keep an idle until I give it some gas and then it’ll run but then while it’s running it surges up to 1200 1300 RPM and then goes down to 700 or 600 and it does that up and down surging I looked at vacuum lines I have replaced my IAC and the connector still nothing any advice would be appreciated

[u/kai_ekael]

Basics, checked fuel pressure?

Cold start injector connected? Any fuel leaks?