My 2003 a4 1.8T with 92k miles wouldn't start this morning. It would turn over and then in about 5 seconds the engine would rev down and shut off. I eventually got it started by pumping the gas in those 5 seconds. It's not an imobilizer problem as I got that fixed and that light doesn't pop up. The only light that pops on is the battery light, but I don't think it's the battery since all the electronics work fine (lights, horn, radio). The car does seem a little sluggish once I got it started. Could it be a clogged fuel filter? Or fuel pump? How would I tell the difference between the 2? Anything else I should try? What else could be causing the problem? I was gonna change the fuel filter regardless as I bought the car with 80k miles and have no idea when the previous owner changed it.