Check engine light on?

This could be many things, it could be spark arcing from your plug wires and causing shorts, it could be a faulty plug to one of your sensors, it could also be that you got some dirt or mild rust build up on one of your screens in your injectors(I doubt this one though), it could be a bad fuel pump and the computer is scrambling to make up for the lost output of the fuel pump. More than likely it is in your ignition system somewhere, take it to a dealer and you will find it to be cheaper in the long run for them to diagnose it instead of keeping on replacing random parts. Trust me, you will be glad you did.

Lets use this guide to help find out

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

I have put it on a scanner and no one can tell me why the light might be gone for a week or an hour. I am a quad mech. So I do under stand what you are saying will the screens in the injectors be clean able?

I have never had to clean the screan on an injector but I do know that this is a random problem with some of the older trucks. Electrical problems are hard to diagnose unless the person looking at it is an expert, it really does sound like an electrical problem either with the ignition system or something that controls the ignition system. Some vehicles have an ignition model on the engines equiped with a distributor and this can be the cause too. If you have a wire that is backing out of a plug or a faulty wire that is almost broken, this will cause it too. A good way to find the electrical problem is too have a person sitting behind the wheel of the truck while you do a shake down on the wiring system and have them tell you immediately when the light comes on, this will help narrow down the location. If it is something like an ignition module, or relay, then what is happening is that after a while it gets too hot and it sets off the idiot lights on your dash and if this is the problem, you will notice that it is gradually getting worse.

Thanks will give that a try

I have a 2001 Dodge Dakota Quad Cab Pickup with a 3.9L 6Cyl, Automatic transmission, 102,500 miles. I bought the truck about a year ago from a friend in our neighborhood (the original owner).

The truck runs great, but on humid or high moisture days my truck starts throwing PCodes. It will start by throwing a P0152 and then later throws a P1740. The next day the check engine light will turn off and I check the PCodes and they are gone. The truck runs great again! Sometimes if I disconnect the negative post and turn the ignition to on and then off to clear the computer and reconnect the neg. Post the truck runs great again. What is going on? The transmission seems to be strong and will climb a steep hill with no problems (also accelerates up the hill). There is no slippage in the tranny.

This past week on a extremely humid day, the truck disengaged the Overdrive and switched the transmission into 3rd. I limped home and the next day I started the truck and it was fine again.

On days that the temperature is below 45 degrees F, the truck runs like a new truck. I spoke with some of my Dodge Truck friends and they seem to think that I need to pickup some electrical paste and coat the connecters on the computer / wiring harness. I don't understand what is going on. Is my computer getting ready to die? Can you shed some light on this mystery?

Many thanks!

How old is the air filter?

The air filter is about 4-6 months old. And is clean.

Last night while driving, my torque converter started slipping. Lots of noise. I made it home and parked the truck on the street. Ten minutes later I fired up the engine and the transmission was working again. I was able to drive the truck up our steep driveway and park it. Oh, no sounds from the torque converter either. It almost sounds like the electronics in the tranny are going out. Could be the Torque Converter Control module and/or the Overdrive Sensor have started to go bad.

By replacing the powertrain control module will that fix the problem? If so, were can I buy a PCM for my truck, localy?

Light came on so I had it hooked up to scanner, it said 02 censor bank2/1 was bad so I replaced it and reset light light came back on after 200 miles code said slow 02 censor 2/1 but while we had it hooked up all 02 censors were working prop except 2/2 it was working very slow so we changed it and reset light light came back on after 300 miles same reading slow 02 censor 2.1 but scanner shows they are working prop I was told comp mite have to be reprogramed or updated or I mite have to get 02 censor from dealer. Sensors were from carquest can you help

Wondering why my engine light comes on and stays on for a couple of months, then one day it will go back off and then again comes back on.

My sensor is good, the fuses are good, and the spark plugs are new.

It says a small leak but where could the leak be?

MLI comes on and remains on while driving. Took it in and the did a diagnostic test and said they thought it needed the fuel system serviced and new plugs. So they put 8 new platinum plugs and did a 3 step fuel injection service. I drove it for 5 miles and light came back on. They took it and reset it and light came back on. Now they are suggesting it news new fuel injector, but said to drive the truck for a while to let chemcials run through they put in. Any ideas about the problem would be appreciated. Thanks. Carla

Have a '01 dakota ext cab 4wd with 3.9 my MIL light has come on. Truck runs fine under 40 mph, but once over 40mph MIL starts to flash and truck stalls and has no power. Any ideas? Also my cruise control light comes on when pushed, but I can't set the cruise. Could this be a related problem?

Engine Mechanical problem
2001 Dodge Dakota V8 Four Wheel Drive Automatic 90000+ miles

My truck has been idling oddly for some time now. It usualy occurs at low speeds but mostly when stopped or just starting the truck. It used to idle at around 1000rpm but now will jump to about 2000rpm at times. Just recently I replaced the TPS becuase of the check engine light but still have the problem. I see from researching most say there is a vacuum leak. Is that the best bet? If so how do I check?