98 Dakota idling problem solved - for now

Hello all, I'm new to the forum and was searching Google for answers when I stumbled upon automotiveforums.com. I thought about signing up to share my problem with my 98 Dakota 3.9L. That was this morning, but now my truck starts and idles perfectly!

Here is what happened:

Went to start my Dakota this morning and it acted like it was but as soon as my foot left the gas, it stalled, immediately. I tried turning it over again, nothing. I gave it some gas, something I was told never to do on F.I. vehicles, but it spit and sputtered and came to life and as long as my foot was on the gas it was OK. I could hear the fuel pump click on and off when I turned the ignition so I knew that was OK. I thought maybe fuel filter or throttle control of some sort. I disconnected the throttle sensor on the side of the intake (I believe it's a throttle position sensor), turned the ignition and nothing. I reconnected the sensor and it turned over and it idled beautifully. Now, did the computer reset itself after I disconnected/reconnected the sensor between cranks? I don't really know, but its possible. This was plain good luck and a lot of troubleshooting experience but mostly in the computer technology field. Now I'm not sure if the sensor is bad or the connector was unseated slightly. I'm gonna have to get a manual before I buy a new sensor, but I think they are inexpensive anyway. Just thought I should share with you all my first problem with my 98 Dakota.

Pete

Hey Pete, I believe I have the same starting problem with my 97 Dakota 3.9L.
At first it was doing it once or twice a week, but now it seems like everyday.
I have taken it to the local Dodge dealer 3 time already and they cannot recreate the problem at all.
It never fails, I take the truck back home, and the next morning...won't start and stay running unless I press the gas pedal.

The service advisor tells me from the symtoms that I describe to him that it's the fuel module (fuel pump) in the gas tank going bad.


Marvin

Marvin,

You know, to tell you the truth, mine was sort of the same way. It did this idle problem once in a while (actually twice) and then after a week or so, kaput. I strongly believe that what I did "cured" my truck's problem.

If you feel up to it, you can disconnect the throttle position sensor on the left side (driver's side) of the throttle body. Then attempt to start the truck with it disconnected, it should act similar only it won't hold an idle AT ALL. Then reconnect the sensor and try starting again and you may have a perfect idle. You won't harm the sensor or computer, all it does is sends a signal to the computer that the sensor isn't there, then after it's reconnected, it causes a reset mode for that device in the computer. I'm no expert and this may or may not be the problem, but I suggest giving it a try. Good luck with your truck.

Pete

Marvin,

Also, my truck has run perfect ever since I performed this procedure.

Pete

I worked for my truck. It wouldnt idle unless I kept one foot on the gas peddle and one on the brake.
I removed the throttle sensor started it up turned it off, reconnected sensor and it worked perfect. Now the check engine light wont go away.
But the truck idle's perfect and runs good.

I worked for my truck. It wouldnt idle unless I kept one foot on the gas peddle and one on the brake.
I removed the throttle sensor started it up turned it off, reconnected sensor and it worked perfect. Now the check engine light wont go away.
But the truck idle's perfect and runs good.

Hashman,

Cool beans, glad it worked for you, too. How long has the check engine light been on? Mine comes on once in a while, but not often enough for me to be concerned about it. Plus it still runs fine. I believe there is a way to reset the check engine light. Let's look into it...

-Pete

Hashman,

Cool beans, glad it worked for you, too. How long has the check engine light been on? Mine comes on once in a while, but not often enough for me to be concerned about it. Plus it still runs fine. I believe there is a way to reset the check engine light. Let's look into it...

-Pete

There are a few ways you can clear your code:
1. The recommended procedure is to have a scan tool and clear the codes. You can visit your local auto part store and have them do it for you, they can do this free of charge.

2. Disconnect the battery for 30 seconds. This works but, you run the risk of opening up another set of problems causing your computer to go into a re-learn mode and have decreased performance until it reprograms itself.

I have the same problem, my 98 DAK will start then stall. If i apply gas it will remain running. I have replaced the TPS, MAP Idle\air and crankshaft pos sensor. when it is running it is fine. it has trouble starting after sitting off for an hour or so. If i let it sit overnight, it starts right up. I tried the trick you outlined , i unplugged the TPS, started the truck, turned it off then plugged it back in. Restarted and it still sounds bad. The fuel pump is working ok. The dealer did not find anything wrong but reflashed the computer software. Is there anything else that could be causing this issue?

I might add, having had the same problem that the MAP sensor airway might possibly be blocked and that a cleanout with the appropriate solvent might also assist. I replaced the MAP sensor on my 93 - 3.9L and still had an issue, until I cleaned the passage to enable the mixture to be OK. Just a thought.

Replace or clean your Idle Air Control Valve (motor). I had this same problem. The engine would stall without giving it gas, started once it a while then got worse. I took it out and cleaned it, it gets a lot of carbon build up and will stick not letting any air in at idle. Cleaning worked for a while. Then started acting up again. I replaced it, havent had a problem since.

My '96 3.9 has a similar issue and I did replace the TPS - admittedly with a used one but it was from a perfectly good running donor vehicle. I just switched them without the starting up in between, though, so I will give this a try. I assume that just unplugging it is good enough - don't need to remove it? My idle is all over the place - it acts like it is possessed or something! The revs will go up and down as it sits there running but never quite cuts out. What it does to me on the road is to splutter almost to a stop as you are pulling away from stand-still, as if it is running out of gas - or more likely flooding. It will sometimes pop and bang and pumping the gas pedal usually clears it fairly quickly and it will then take off. Takes a lot longer to clear it when it happens now, though so I am not using it much until I get to the bottom of this. My other thought is the cheapo o2 sensor I got off eBay a couple of years back might be to blame as I do get a code for that occasionally but it comes and goes. As I said, I'll try the TPS trick and I have an o2 sensor off the same donor truck so I'll see if that helps, too. Otherwise.. Any other tips, guys?
Many thanks in advance.