1999 Toyota Camry CE sluggish acceleration

I have 1999 Toyota Camry CE with 4 cyl engine and auto trans. Recently it’s been idling rough and acceleration has been very sluggish. I changed the spark plugs and wires today and it seemed to fix the problem but after driving 30 miles it came back. What else could be the problem? Thank you for your help.

Is the Check engine light on?

Go here: http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?fromSearchPage=true&pageId=0900c152801a8f28&partName=Removal%26Installation&partId=0900c152801a8f28 , register, follow the instructions for changing the fuel filter. The fuel filter is under the hood, below the brake master cylinder.

Check engine light is not on, the acceleration sometimes is good and sometimes is very slow.

Today I took out the fuel filter and when I disconnected the inline (from fuel tank) I was expecting fuel to burst out since I was told it’s under pressure even when the car is off, but there was no pressure at all. Could I have a bad fuel pump?