83 240D

Symptom: In the morning or just after not being started for a few hours. Car will either take forever to start (like it needs fuel) or drain the battery trying.

Temp Solution: A shot of starter fluid in the intake tube will fire it right up. but obviously isnt good for it.

Since the problem started i have verified the glow plugs, relay, battery and fuel primer pump plunger are good.

what should i look into next? valve adjustment? something with the fuel?