lousey fuel economy on 305 tbi

I have 305 tbi with 3000 miles on it. rebuilt the heads and block and tbi............... Have been driving her and notice my fuel economy is really bad best 14.5 worst 7 mpg. So far changed my map and o2 sensor no change. Hooked it up to my friends computer and was wondering about the block learn code ....... another mechanic suggested maybe something in the emission system is out of wack...... perhaps that might be causing the problem. As of right now I have to readjust my rockers....... but for the most part haven't been able to lock it down. I also notice a miss at low idle right now she's set a little low at 500 or so I have to raise her up to 600.................. I am running a hypertech switch, cooler fan switch and a 180 thermostat and a 3 core rad.

Any help or suggestions is greatly appreciated
Kenny

try changing the t\stat to 195 or 192, it may be that your engine isn't going into closed loop, although it should be, as far as i know it should go into closed loop at about 165 or 170, just a thought, good luck