WHy is my 91 Nissan Pickup Sputtering so bad?

[chaddeihl]

1991 Nissan D21 Pickup - 4cyl - 2WD



I've replaced the plugs, cap, rotor, & wires and engine still sputters when accelerating in neutral. The only other thing I can think of is a fuel filter, but I have not replaced a fuel filter before in this truck. Hoping its not a bad o-ring. The 4th spark plug at the rear of the engine had a little wet oil around the firing mechanism, which I think can be somewhat normal - rest of the plug was clean. Cant figure out where the miss is coming from.

Does this pickup have 2 fuel filters? It has a carburetor so I am just wondering or is the only filter back near the gas tank?

Thanks for any help.

[Towncivilian]

The fuel filter is in the engine bay right next to the power steering fluid reservoir. Be sure to release fuel pressure by removing the fuel pump fuse and starting the engine, then waiting for it to stall. Crank the engine a few more times, then replace the fuel filter. Make sure you have some rags handy for the fuel that will spill out.

This vehicle should not have a carburetor.

[chaddeihl]

I meant to say the truck has a large air filter on top not the carburetor, lol. Is the fuel filter underneath the air filter in this pickup? or is it easily reachable without removing it? I will check again tomorrow in the daylight. When replacing the filter, does it require removal of the pump itself? thanks.

[Towncivilian]

It should be accessible without removing anything. The fuel filter is an in-line filter located adjacent to the power steering fluid reservoir in the engine bay.