Not always, it could be a vacuum leak or an idle motor problem etc. Do you have a Check Engine Light on? This will really help if you can get the code retrieved.
It is pretty easy for a pro tech to check the fuel pressure. It should not take more than a 1/2 hour of shop time. At least then you would know. How does the car drive on the road? If it was the fuel pump, it would have NO POWER AT ALL. Eventually a code will set for an overly lean oxygen sensor.