Hey guys really need some help, advice and opinions on what could be the issue with my 97 impreza as I am running out of ideas on what is wrong

My car starts fine, most of the time it will idle at the 1, put it in reverse and it will go just under 1, sometimes the car will start then slowly clonk out and will take a good 6 times to get it running. It doesn't have any over heating issues or make any weird noises while driving, however it tends to die while driving sometimes it will come back to life and keep going but other times it will just die and I have to pull over, turn car off then start the car again. When the car does clonk out while driving or waiting at lights the stereo continues to play music. So far I have replaced

- Spark Plugs & Leads
- Fuel Relay
- Fuel Pump
- Fuel Filter

Will be buying a coil pack in the next few days and a K&N air filter, after that I am at a loss on what the issue may be...any help would be great as I really dont want to get rid of the car.