I have a 92 Dakota, 5.2, 318. A while back on my way to work the check engine light popped up while at a stop sign, and it was running a little rough, kind of stumbling with poor acceleration, especially up-hill. At the time this would only happen if i had been driving for 20 min. or more and stopped and idled like at a stop sign.
Well it has steadily gotten worse. I've changed my oil, spark plugs, used gas treatment and injector cleaner, replaced my fuel filter, checked my fuel pressure which was slightly low but not enough to cause such problems. None of that helped.
For about a week it started to run okay again and then it just started running like crap, poor acceleration, rough idling, check engine light is always on, it almost sounds like its missing, there's more smoke from the exhaust than i ever noticed before, and you can smell gas, which it uses up like crazy now. A few times when looking under the hood I've noticed a hissing noise coming from somewhere around the back behind where the air filter goes but i can never find exactly where it comes from. I don't see any loose vacuum fittings or connecters or anything like that. The truck will run but not very good and it uses so much gas. I'm afraid to drive it for fear of making it worse.
My first thought on this was the fuel pump but now I’m leaning toward the idea of injector problems of maybe a sensor somewhere.
Anyone know what's going on here? Any info would be greatly appreciated. I'm stuck driving a mini-van to work everyday (at least its a dodge) but i miss my truck!!!

 

Go here to pull the codes, and than post the codes up here.

 

Thanks!. Ok, Here's whatI got..........

12 = Direct battery input to PCM was disconnected within thelast 50 key-on cycles

15 = No vehicle speed sensor signal

27 = Injector control circuit

........not sure what PCM is, or any of these really. The injector control unit, i can only guess thats something with fuel injection, which i'vebeen wonderingabout.

 

have your O2 sensor replaced, i had a similar problem, running rough , gas smell, poor mileage,diagnostic said engine was running lean and theyreplaced the thermostat and O2 sensor

 

The PCM is the Powertrain Control Module. It's the engines (and on these vehicles, the transmissions) computer. It recieves input from many differant sensors, and uses these inputs to determine the correct way to run the engine.

As for the code, the PCM is not sensing the correct change after the injector is turned off. Unfortunatly, these olders computers don't tell us which injector is causing the code. There is one injector per cylinder, and the injector is, more or less, mounted above each cylinder. (See picture)
You can use an ohmmeter to test resistance of the injectors to see iftheir good. The resistance should be ~14.5 ohms.
If that is good, connect a test light to one injector at a time. While cranking the motor over,the light should flash.
If the light doesn't come on at all, either the PCM is not providing a ground for the injector, the injector is not getting power from the automatic shutdown relay (ASD), or there is an open in the wiring. You can test for continuity between the positive lead of each injector connector and the output of the ASD relay(see picture below, the output of the ASD relaywill be terminal 87, which will be stamped on the bottom of the relay). There should be continuity.
If the light stays on, either the PCM is not provding the proper pulse (i.e. shutting off the ground for the injector), or the circuit is shorted to a ground. You can simply test for continuity between the ground pin of the injector connector and a known good ground. There should be no continuity. Alternitivly, you can also connect the groundlead of a voltmeter to the ground pin of the injector connector and the other lead to a known good positive power source (such as, the positive battery post). There should be no voltage reading.
FYI, the dark green and orange wire at every injector is the power wire. The color of the ground wire isdifferant for each injector.

If you need more help, clarification, or anything, just post back.

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Much appreciation!!!
I will check all this stuff out. It may take a few days.I'll haveto borrow the testers and get a buddy of mine to help me out. i'll post back with any conclusions or problems. thanks again

 

I would prob suggest the O2 sensor aswell especially if the fuel consumption is that bad and it is smokin black

 

i know its been forever since i posted but my trucks been at the mechanics for several months now, and finally he told mehe thinks it's "valve guide seals" wearing and letting too much oil in. He quoted me about $250 to repair it and also said it might not fix the problem as it might need rings. i'm about to say screw it and sell for what i can get, and get a different truck but i really love this one. so i'm gonna try and get some other opinions and see what my options are (possibly rebuilding or replacing the engine) i mentioned O2 censors and pulling up codes and what they said, butthis guyseemed to almost disregaurd all of this. What do you guys think? Does this seem like it could in fact be the problem, or should i take it to someone else?

 

take it to someone else for a second opinion, if the vehicle is puffing black smoke, check the o2 sensor, for the hesitation, check the EGR valve, you didn't mention it, but if you got blue smoke at all mech could be right about guide seals, but in all my years I've never seen a 5.2's valve guide seals go bad, maybe I'm just lucky but I've actually never seen a 5.2 puff blue smoke.I've had hesitation issues twice on my '95 and once it just needed an injector cleaning, 2nd time itneeded a new EGR valve, 209K miles on theoriginal untouched motor, still has original o2 sensor and no symptoms. Hope this helps.

 

had another friend look at it, as of yesterday, gray smoke, very sooty (wifes car was parked behind truck , the dual exhaustblew soot and left two black spots on her bumper ...ooops)checked plugs they aren't fowling out or oily, but you can tell the truck is getting too much gas.he told me that if the O2 sensor isn't the cause it most likely needs to be replaced by now anyway. having hell getting it off though. we also unhooked that battery hoping the computer memory will reset and then we can pull the codes again. didn't really get a chance to look at EGR valve yet....is there a way to tell if an O2 sensor or EGR is bad by looking at the part?