My winter vehicle is a 91 Dodge Dakota. Its getting pretty old with 134K miles on it. I'm having a problem with the idle starting the truck up, and I was wondering suggestions on where to look. It has to be some sort of sensor or something.

1. When I start it up, by just turning the key, it turns over, to about 500RPMs then imediatly dies within a second. However if I start it while pressing the gas pedel, its fires up just fines and doesnt die.

2. Now when it dies, it does give me the lights of a Check Engine, as well as the oil can light shows. Is this a code, or is it just because my key is in the accesory position? Could advance or somewhere pull this code?

I replaced the air filter that didnt really do anything. Its gotta be some sort of throttle position sensor or an idle sensor. Any ideas? I hate to start buying costly sensors and replacing them on this old of a truck without knowing exactly what the issue is.

 

Sounds like it's not getting enough fuel in if you have to hold the pedal down to start it up. That's reminds me of some trucks in the past where I had to pump the pedal down before turning it over. I'd look into the cleaning the carbs (I presume it's not FI) which are rather simple with carb cleaner and taking them apart. Something inexpensive as this should help. If this does nothing for you then check the throttle linkage. If none of that helps then you'll have a bit of sherlocking to do. My money is on the lack of fuel intake through the carbs since it sounds very similar to older trucks I've driven in the past. On top of that you can simply add fuel additive to the tank that cleans the nozzles out to assist with this.

If you had air trouble then you would of had a bit of backfiring, popping and dark smoke from the exhaust running so rich with lack of air to get the proper mixture.

I doubt the lights are a code; they're the lights that are just displayed when the key is in the "on" position like any other vehicle. You can go to AutoZone, Advanced Auto, NAPA or any other known auto part store and ask them to run an OBD II diagnosis on it which requires them simply hooking up the scanner to your OBD II port under your dash and reading what the issue is.

 

It is actually Fuel injected.

 

Ah, my trucks in the 90's weren't, anyhoo. In that case, I would get it diagnosed first. If nothing comes up try checking your fuel filter and replace it if needed. When was the last time you did this? What the mileage? Also add an injector cleaner into the fuel tank when on empty in your next fill up. Lastly if none of this helps for simple solutions and if you have the mechanical know how, I would also suggest taking off the injectors and cleaning them out as well.

Regardless, it sounds like a lack of fuel issue which could be lacking due to an old fuel filter, loss of pressure to supply the fuel or the injectors needing cleaning, worst case possibly replacing them or could be something as simple as an O2 sensor.

Edit: Actually shoot, a '92 chevy I owned was FI, and when I replaced the fuel tank from rotting had a similar issue as you, resulted in the O2 sensor getting replaced due to improper fuel / air mixture which was lacking fuel. I would recommend getting it diagnosed first to pinpoint the problem. The O2 sensor should be easy to replace if that's the issue. Then after that work down to the filter and cleaning.

 

Will do. Thank you. I replaced the fuel filter last year, less than 10K miles ago. I'm going to try the fuel injector cleaner in the gas tank first then to the O2 sensor.