I have a Goodman GDH 80703AXAC furnace it runs for about 30 min then shuts of on high limit then will allow relight? Any ideas what is going on?

It sounds like you have an airflow problem. If you have AC coils they are probably dirty and need cleaning. Also, you should pull the blower and clean it well. Just 1/16" of dirt in cups of the vanes on blower wheel will reduce airflow by 33%. Clean it well with coil cleaner and get the airflow up and it should work fine. DrTom4444

Thanks drtom44 you are a big help thans

You are welcome. Dirty coils is a problem that is often neglected and a problem scam artists use as an an excuse to unnecessarily add Freon to you unit in an effort to raise suction pressure to keep it from freezing over.