Hey guys! I am new to this forum, but I figured it was the best place to get some info for the running issue on my 1990 Dakota 3.9L automatic. Some background info first.

The truck was only used as a spare work horse pretty much. For the past how many years it was never driven in the winter and just stored. It would fire right up in the spring no problem. Well, this year I am storing my restoration project/DD for the winter to work on it and decided to drive the Dakota this winter. It has been driving fine up until last friday. Onto the problems.

It started to kind of bog and surge maybe once everytime I drove it. Throughout this past weekend it progressively got worse to stumbling/hesitating/stalling/surging when idling and when cruising. Now its to the point where it doesnt really wanna idle barely.

I replaced the plugs, cap and rotor last night to no avail. The store gave me the wrong wires, so I will be replacing those most likely tonight or tomorrow. I really doubt that will fix anything tho, but ialready paid for them so why not throw them on. I have been reading threads and it seems like it could really be anything. The kicker tho, is that this morning before work I tried starting it and it idled for a couple seconds and died. Started it again and it idled for awhile but very crappy. I also smelt fuel after a few seconds of it idling, so what could that be?

I would really appreciate some help since I dont have another car to drive now and need to get to work and stuff every day. Thank you so much in advance!

 

It could be a bad ERG valve to vacuum leak to low fuel pressure. Do you have any check engine light codes? Simple way to check them, check the FAQ in this section (just a few posts above this one).

 

I knew I forgot to mention something. I dont get a check engine light or any codes when checking. Thats the biggest thing thats confusing me.

 

I have the same issues, I can hold steady gas with my auto, not moving the pedal at all..its surging and going up and down like crazy even on the tach, stalling and sounding like a popcorn machine under load. One of my guys told me to check the egr and smog pump, dont think ours have smog pumps think thats the early models that do. only does it after it warms up. problem started about a week after I replaced my O2 sensor, splice is perfect, IAC is shot though and have a blown plenum.

 

Mine is the early model I think, since its a 1990. I heard that they overhauled the 3.9L in 92? Am I right on this? Hhmmm so I should check the egr and smog pump then, huh? Where are these located by chance?

 

im going through the same problems...today i found that the little short hose on my egr valve was leaking i replaced it and so far no problems so id start with that..but keep me informed just incase that wasnt the problem with mine lol

 

The hose running off the side of the egr going to the top of that other solenoid thing next to it? I will keep you informed.

 

I checked the hoses on the egr and they are all good. I even checked the egr by sucking on the hose and it sounded like it was opening I think. Now what?

 

unplugging the IAC makes the rpms surge up, but you can still hear the bogging and whatnot.

unplugging the coolant temp sensor makes teh truck run a little bit worse and die more often.

tried out a spare coil i had laying around from another car and it still acts the same as with the old coil.

any suggestions?

 

Would the VSS or whatever sensor is at the back of the transmission have anything to do with my running issue? It looks pretty nasty all around there.