Several weeks ago, I noticed one afternoon my Dakota 3.9L 5 speed 2 wheel drive would shut down at stoplights when I let off the gas. If I kept revving it a little, it ran fine. This happened several times, then stopped. I'm thinking Idle Air control valve, but haven't touched it yet.

A couple weeks' ago, started the truck one afternoon and it started running very rough, backfiring, and sounding as though it was on 3 cylinders. I kept it going and noticed that if I let the truck idle down, it ran smoothly, but backfired and ran terrible if I tried to give it some throttle. This time it set a check engine light. I shut it down, waited a couple hours, and tried it again. It ran fine once again, but the check engine light was still on, so I drove it to an AutoZone and they scanned it for me. Codes were P0320, P1391, and P0351. They thought since I had just filled up with gas, it was probably bad gas. I put two bottles of STP gas treatment in it, and have a third one ready when the tank is empty again.

Tonight, I drove it a couple miles and on the way home, it started running terribly again, check engine light is on again, and again after parking it an hour, it ran fine but light is still on. I checked the procedure for getting the codes out of the computer in my Haynes manual, tried it, and got no codes. The check engine light is on but never flashes.

Any thoughts from anyone who has had this happen? I'd hate to spend a lot on labor rates if this is a sensor failure that I can easily address on my own, so any help would be appreciated...thanks all.

 

sounds like your coil is bad to me. a bad coil will do just that crap out after about 5 min when the engine bay gets hot so does the coil and it craps out

 

i would check the coil, and maybe the 02 sensor?

 

my 5.9 did the same an it was a o2 senser

 

Thanks for the help guys. I have looked up the codes, and one of them does mention ignition coil as a possibility. The other two codes look like crankshaft position sensor and camshaft position sensor.

I'll need to check back in once it gets sorted out. This is a bit over my head....

 

Got it back from the shop today. They saved the old sensor so I could see it. They think the dripping antifreeze from last spring's leaky intake manifold gasket caused it to corrode. I must admit it did look terrible.

Let us hope it stays out of the shop for a while!

Thanks for all your ideas.

 

which sensor did they change

 

I'm betting it was the crankshaft position sensor....
ccfish

 

this may not be your trouble. but next chance you get . take take the disturber cap and plug the vent hole. i use JB-weld. it will keep the moisture out. took me 4 years to figure it out.

 

It was in the title of my earlier post, but yes it was the crankshaft position sensor. Drove the truck to work today and all seems well. Chrysler is mighty proud of those little plastic rivets used on the wheel well shield.