I have a 88 audi 80, up until yesterday it was cutting out when driving, would feel like it was shaking but engine would stop and start while driving like it was cutting out, turn off to put gas in and now it starts but will not stay running, pushing gas pedal does nothing, acting like it is getting no gas to stay running, but will immediately start again when I turn key. Any idea's? I am thinking fuel filter or fuel pump but I am reading thoughts on here of other things.