I have a 93 chevy lumina with 164,000 miles on it. Recently I have been experiencing very rough idling with it where it will idle very high right after starting then gradually idle lower but being very choppy/shaky. Today I drove it to the store and when I went to leave it started then stopped 5 sec later the only way I could get it to start up and keep started was to give it gas. Then When I began to move everytime I would stop it would die. I had to put it and neutral and apply pressure to the gas to keep it from dying or idling very roughly. What could be the problem? The electrical seems fine. Any ideas?