[Confused and frustrated]

Ive had my 91 subaru legacy for almost 6 months and never driven it. I bought it because it needed new head gaskets and my friend is a mechanic. We changed them together, by the book and all. it sat for a couple weeks in peices but it went back together perfectly, we think. It will not run properly after it warms up. The idle is good for appx. a minute, and then become choppy until it eventually dies. After that it wont start good. The temp gauge doest work, and it is showing the same symptoms of as a possible MAF sensor problem or a Ignition coil problem. Both work fine as we checked. We gave in finally and sent it down to the Local Subaru dealer so they could use their diagnostics machines and know-how to fix it for us. No go, they cant even figure it out, all they cuold think of was valve timing and it was fine. PLEASE HELP ME!!!! I need to drive this car before the snow flies, whatever help you can give would be GREATLY appreciated. Thanks.

[2.2 Troubles]

my 1990 Legacy, we changed the head gaskets on it because it was overheating. And Now that weve put it back together it doesnt run like it did before. It stutters and eventually chokes out and dies. Im unfamiliar with Subaru engines, as this is my first. If anyone can help me with a possible problem i have, please let me know. Thanks.