hello, i just bought a 1992 3.9L dakota. the last owner sold it out of frustration due to its poor running. he says it ran fine till about a week ago when it died at a gas station on him. he said it would start and idel fine but as soon as he gave it any gas it would bog then die. he towed it to a small shop where they tested the fuel pump replaced the fuel filter, cleaned out the fuel rails and replaced the fuel pump relay but the truck does the same thing. i tryed taking the codes but only got a 12 and 55 .12 being that the battery had be disconnected. i tryed strarting it but it seems that some one had cyphoned the fuel out of it durring the night so it only ran for a few seconds then sputtered and died. the only thing that the shop recomened was to try replaceing the map sensor. does anyone know what might be my problum i think it migt be a sensor but am not that sure

 

it may have sucked up some crap when he ran it out of gas and they did not get it cleaned out good.

 

Under throttle bog can also be caused by a weakness in the ignition system, check out the plugs, see if the wires are burned or feel floppy , open the cap and look for etching or wear. If all else fails, a full tune-up is a good cheap starting point to ruleout the common culprits...

 

ok so heres a update, i got the truck home and have done some playing around, i put new o rings on the injectors to stop them from leaking and found a loose spark plug wire. the truck is still rather hard to start but once it starts it will idle fine for a bit then start to get a misfire but it wont die it will miss for a bit then smooth out and run alright again, it idels between 200 and 700 rpm depending on if its misfireing or not. it still bogs if u try to give it much throttle but if i feather the peddel i can get it to rev up and it seems to run a bit smoother when its reving higher. i let it idel for about 45 min and i checked the codes and still only got a 12 and 55. i think i might try going through the ignition system or try replacing some semsors. any ideas? thanks

 

well i droped the tank turned out to be a damage fuel line in the tank the one that goes from the pump to the hard lines out of the tank, runs like a champ now

 

SWEET! good deal man, got me tempted to drop mine to see what it looks like in there lol