this sounds like it might just be the idle circuit
not working.you say it stumbles & such until 2200 when it comes clean & away it goes.what idle jet/s does it have in it?what about the idle mixture screw,how many turns in or out is it?
the 32/36 i've got on my a15 has a 60 idle jet
in it,due to various things happening to it,& it looks like it needs a 65.stock off a 2l ford is usually 55 on the primary side & 50 on the secondary side.when you quickly give the throttle a slight touch,does the engine sound like its drowning?these things can all affect how the engine pulls off idle,& can cause the car to be awful to drive.on the other hand,if they are right,the car could be a joy to drive.hope this helps in some way.