2000 Toyota Solara 4cyl. manual a/c will blow cold air for a while then it blows warm air. Sometimes from all vents other times just from driver or passenger side vents. Compressor is kicking on when

might need to get the a/c charged or you might have a leak. if you have a leak you will smell the Freon coming thru the vents while a/c is on

Yours is about the age that vehicles start having problems with the vacuum lines. Those lines are used for lots of things. One of them is controlling of the air deflector door(s) inside of the air box. Under the dash this box has both the heater core, and the a/c evaporator stored in it to give us the heat and cool air any way we want it. The evaporator is where you get the cool air, and the heater core the warm air. The door(s) are controlled by the switch where you change the air direction from the floor, to vents, to defrost, and heat to a/c, or blend, using the temperature control switch. Look under the hood at all of the plastic and rubber hoses leading away from the intake manifold. Vacuum is created by the engine running and the air the engine takes in to mix with the fuel in the combustion chamber. The vacuum is also stored in a vacuum canister under the hood. Lines from that canister or the manifold are likely to be your problem. Cheap fix and you can do it yourself. All auto parts stores have replacement lines and connectors. Good luck.