I have a 1997 nissan pathfinder and just recenly it has been hard to start you have to step on the gas for it to turn over. I replaced the fuel filter and it started fine for a little bit and know it's back to starting hard again also it shows a knock sensor code when i hooked it up to my scanner eventhough the light wasn't on. Any suggestions to the problem thanks

What's your mileage on the vehicle ? Have you checked fuel press. , good spark?

69,000 no i have not checked those

Well, your knock sensor won't turn the mil on, and I seriously doubt it is the source of your failure. Try looking at the terminal ends inside the dist. cap, and look for any funk that may be built up. You may want to start with a tune-up, seeing as how the ff seemed to make it start better for a while. By mileage some of your ignition components are still good, (s-wires) however if they are O.E., they may be breaking down due to age and heat. If you do decide to change anything however, stick with O.E. parts less problems. Hit me back.

could it also be the fuel pump

It could be ten different things. How's your air filter? Are the plugs, wires, cap and rotor all new? Cleaned your MAF sensor or throttlebody lately?