Hey all. I've got a problem that I can't figure out. I have a '94 Civic DX w/ the D15B7 motor and 240k + miles. I've recently replaced the radiator, cooling hoses, thermostat, water pump and timing belt. This has fixed the overheating problem but now the transmission doesn't want to shift. The car starts right away but idles a little rough. Plugs, wires, cap rotor, coil is all good. When I start driving it shifts from 1st and 2nd a little hard and then the engine has to rev up to get 3rd into gear. After in 3rd it shifts to 4th just fine. I've heard the Idle Air Control Valve may be the culprit. I don't know if there's a way to check the function of it before I spend another $100 on a new one. I've also checked the level, color and odor of the tranny fluid and that looks good. Any ideas or suggestions?

P.S. The car isn't equiped with an EGR valve.