my 90 accord 5 speed when i got to turn it on after its been park for the night it will turn over and turn on but starts to shake and ill press on the gas a little so it can stay on but when it goes lower than 1900rpm itll shake bad then shut off until i turn it on again then itll stay on im not exactly sure what it is.

 

Does it do this until it the engine warms up to operating temperature, then smooths out? Or does it do this no matter how long the engine runs?

Do a search on this site for FITV and IACV. If the symptoms sound similar, refer to this article in the FAQ sticky-ed at the top of the forum for how to clean them.

https://honda-tech.com/forums/honda-accord-1990-2002-2/cleaning-iacv-fitv-tb-1844067/

 

Also, a you need to 'burp' or bleed the air out of your cooling system. Weird, I know. But on your FITV and IACV you will notice all the coolant hoses connected to them. If there is air in the system it plays hell with the operation of these two components which are tied to your idle controls.

It is also a 'free' easy fix, so look on the bright side.