I have a 91 D21; hardbody 2.4l 4 cyl 2x4 5speed. Just bought about 3 weeks ago (first Nissan).

The truck misfires almost as if one cylinder isn't even running. I have tried everything sofar. From a cold start it starts first turn than sputters and idles missing. From a warm start (sitting anywhere from 10mins to an hour it takes about 30 turns of the key to start.

I've replaced fuel filter, fuel pressure regulator, plugs and wires, distributor cap and rotor, fuel treatment, sea foam.. The only thing I haven't done is the fuel pump and tank cleaning, that is next on list. Could this be the problem? Or anything else I'm blind to that I'm bypassing. Let me me know what you guys think.

 

HAve you checked the injectors?

they may be drizzling fuel out of them, instead of misting the fuel out like they should