Ok so ha e a 95 Dakota with the 3.9 liter. Just finished 500 mile break in on new motor. Was driving to work and tried to pass someone. Motor bogged down amd backfired in the intake. Lost ALL power. Took foot out of the gas and it recovered after a few seconds. Also she dies at red lights sporadically. Habe replaces the idle air sensor, map sensor and the tps sensor. Timing looks right with a light. Any other suggestions? At a loss.

 

Timing chain might be off by a tooth allowing the intake valve to stay open a little too long so fuel will go up into the intake in compression stroke and ignite. I've had it happen in a dohc motor before.