I have a 1994 honda accord ex f20b swapped 5speed tuned ecu and when i purchased the car guy told me the car had a vaccum leak so i looked for the leak couldnt find it so i looked up reasons the car would idle funny and found that you should clean the iacv and iatv so i did and it fixed my idle but noe the car shuts off after you rev past 4,000 rpms and let the rpms drop back down so i adjusted the throtle cable and idle and replaced spark plugs and spark plug wires does anyone know what the problem could be? And it only shut off after the car warms up.

 

Once the car is warmed up the FITV closes and idle control is via the IACV.
If when cleaning the IACV only the valve section should be cleaned. If any solvent gets back to the solenoid motor it can damage it.
Do not use the throttle cable to adjust idle. Only adjust to remove slack from the cable.

Most likely the reason the engine dies after a 4Krpm rev is the IACV is unable to compensate for a soft landing back to idle speed after that rev and the engine stalls.