89 d21 3.0 missing

[nissan55]

I recently just bought a 89 d21 se 4x4 an it just started to miss. it runs fine when its cold but the when it warms up it starts to miss an sputter. It gets worse when you give it gas and are going up hills it will sputter and miss at about 1500 rpm to about a little over 2000 rpm. I have replaced the plugs and wires an fuel filter and air filter even checked the vacum lines with no change. what else could do this its not throwing any codes or lights

[nissan55]

any one have any ideas?? its a pain going up hills when you give it gas it will start jerking an missing worse an misses when hot