I have a 3.5 ton gas pack installed in about 1993. The temperature does not stay constant in all rooms. Thermostat set on 70 but main open living/kitchen/dining reading about 66. Large family room reading 65. House is long ranch about 76' straight. Had contractor out and he checked freon, blower, cleaned coils, changed and cleaned filters, changed the confirguration of main duct work and trunk lines. The air is not blowing out of the vents very hard (more of a trickle). It also does not feel very hot to me, however, when he puts his thermometer into the vent it is reading about 90+ degrees. I am tired of being cold. Any suggestions as to what else it could be before I buy a whole new unit. My house is 2,150 sf.