My 2003 Dakota idling a little rough and replaced the O2 senor (right before the Cat)(bought at O'reilly) and after replacing that it seemed to idle a little better but then had times of being sluggish. If I gave it gas it wouldn't want to go, and then if I full it more during that time it would get worse and then after a second it would rev back up and go like normal. It does it randomly when I'm at a stop wanting to go. Then today I was parked for about 10 min to go inside of a store and then when I came out it started fine and I took off and went about 20 feet and it cut off. It started right back up, but what is causing this? Usually when it does this it is warm, and if I let off the gas for a sec or so I can then give it gas and it is back to normal. I also replaced the sparks plugs (Boush +2), plug wires (Boush), and a oil change with a motor flush first then adding restore when filling it back up. So It should be in tip top shape. Could it be the O2 senor behind the Cat? I have also been reading, could it be the IAC?

 

What engine is it? Did you have any codes stored? I have heard the Bosch spark plugs do not do well in the Magnum motors and I have heard from a lot of people the Bosch O2sensors do not work well in Dakota's. NGK is the best and I think NGK is the supplier for the OEM Dodge O2's.

The bad idle could be a faulty IAC, which can be caused by a bad or lazy O2 sensor. Stalling when warm could be indicative of O2 problems. After you put in the new one did you do a hard reset on the PCM? Disconnect the negative battery cable and then hold the ignition switch in the start position for half a minute to reset it.

Jimmy

 

definitely get rid of that bosch garbage and put in some NGK equipment and go from there. could be the plugs fouling up, and a little future reference, that engine restore stuff is garbage, in all the years it has been out, i've used it, my dad used it, friends used it, no difference in anything. at every oil change, put in the lucas oil stabilizer. the stuff is like molasses and sticks to everything, cutting down wear, and fill up and microscopic irregular wear that will cause poor performance, plus theres a detergent in it to cause seals to swell back up to cut down on leaks, wont make them deteriorate either. i use it, and we use it at my college's diesel shop on the trucks we work on.

 

I unplugged the negative cable, but I didn't put the key in the ign. I'll try that. I'll also look into the NGK 02 sensor.

I have the V6 3.9L 2WD

 

Also when I did replace the O2 senor from O'reilly, I'm pretty sure I only have 2 O2 senors, 1 before cat and 1 after cat, but after looking at the NGK website it has one for up stream right (2), upstream left (2), down stream, downstream left, and downstream right. on the V6 3.9L doesn't it just have one upstream O2 senor, and how do you know if you need a right or left?

right (23138) and upstream right (23137) with a different part number, what is the difference?

 

After reading around some more, could this be a IAC problem? And if so do I need to try and clean it or just ahead and replace it? My truck has 137,000 miles on it.

 

Codes from the PCM will tell you which O2 is having trouble, or whether this problem has some other cause. You can have the PCM codes scanned at Autozone or Advance. Not sure if O'Reilley's does it. We don't have O'Reilley's here. You can also turn the ignition key on and off 3 times then turn it on and leave it on and any stored trouble codes will display in the odometer. Usually when the IAC is bad the truck won't idle and it dies.

A bad O2 sensor is probably not related to a bad IAC. It's a good idea to clean the IAC port in the back of the TB and clean the air passage with a toothpick. That is also a really good time to remove the TB from the manifold, remove all the sensors and clean the TB very well with TB/carb cleaner spray and a shop rag. Reinstall the TB with a new TB gasket and lubricate all the linkage pivot points with silicone spray. IAC is not very expensive and you can replace it anyway and do the hard reset on the PCM if yours is bad. Be very careful when handling the IAC and do not touch the pintle end and don't drop the IAC sensor.

There should be a total of 4 O2's on your truck. 2 on each side, one before and one after each catalytic convertor. The ones after the cats do not usually have any problems. You might need to replace the upstream O2's between the cats and the exhaust manifolds. Scanning the PCM for codes may tell you which O2 is bad but if you have a lazy O2 sensor, it won't store a code. Truck won't run right either. AT 137 K I think it's very good preventative maintenance to just go ahead and replace both upstream O2's with Mopar/NGK parts. Stay away from Bosch. The 3.9 runs real well on Autolite 3923 or NGK V-Power spark plugs too. It might help you to get the Bosch plugs out and replace them too. I have no idea on Bosch plug wires. I guess they should be OK but I really like the Belden Premium plug wires from Napa. They work great on my truck.

The 2 different part #'s are just to indicate in the parts catalog whether it is the up or down stream O2 sensor. The sensors themselves should be the same part. Any time you replace parts on your truck you need to reset the PCM. Hope this helps. Let us know how it turns out.

Jimmy

 

in my opinion, change all the o2 sensors at once, yes there's 4 of them, this way everything is fresh and you dont have to go under there again

 

Maybe that was it, I replace one, I thought their was just 2, and I replaced the upstream of the two I found. I guess I need to search for the other 2 and most likely it might be the upstream of that set.

I replaced the upstream on the Cat that is right under the back seat of my quad cab. is the other two up wear the headers meet, I'm guessing. I'll have to do some searching tonight to see if I can find the other 2.

 

Take the t/body off,take out the iac,and clean the throttle blades and bores and iac tunnel good,no carbon left.yes u can touch the pintle carefully,spray it and use a toothbrush to clean the carbon off.don,t have to remove tps sensor to clean t/body,but with that problem ur experiencing could be a tps going out.don't need a code sometimes for stuff to happen.the 3.9 runs rough in nature dut to it's firing order.yes if u want replace all o2's;go for it!o2's over time become lazy true,but you need a dealer scan tool to see that while running to verify switch rate ratio.i see you put junk in for plugs.use oem champion plugs also check for condition of wires,cap, rotor???how is the battery connections{loose,corroided??