96 GC throughs codes 12,43,55
 

My daughter's GC seems to sputter and tries to die,but only when the outside air temp is around 80 degrees. Any idea's?

Code 43 is the only real code you have there, 12 and 55 are nothing to worry about. 12 means the battery has been disconnected at some point, and 55 means the end of the self diagnostic mode. A bad connection at the PCM, a bad coil, or a bad PCM can cause that code. Google "jeep code 43" and you will find useful diagnostic info.