Nissan Repair: nissan z24i, culpret, rotor

Question
i have a 89 truck nissan z24i engine.and when you give it gas at 2000 rpm its like you turn the key off let off the throtel and it backfires.every thing has been replaced on throtel body. i see on the internet that these engines are junk..nothing but prolem after prolem.i was going to sell it .but i didnt want to stick somebody with it.what i can tell nissan needs to get out of the car and truck bisness

Answer
Joe,

Backfire sounds like the timing is off or there is a short in the ignition system for firing the plugs.  I would look at the plugs, wires, cap and rotor and make sure the timing is spot on.

I will say, usually, the distributor is the culpret since it gets contaminated with oil on the optical shutter wheel and that prevents the plugs from firing correctly.  Disassemble the distributor and look for oil on the optical shutter wheel.  This is under the cover that is under the rotor.  Remove the rotor post using a screwdriver and then remove the cover under it.  The shutter wheel is under it along with the LED pickup and receiver.  If there is oil replace the distrubitor with a rebuilt unit.