This is going to sound funny, but I recommend replacing all of the O2 sensors at once. I had this problem on a Mercedes ML 500 - 8cyl, two plugs per cylinder. Ran pretty good but I could always hear it sputtering and popping at idle and had a constant multiple misfire trouble code. I tried a lot of the same things but could never find the problem. Then I came across a factory service bulletin that said replace all the O2 sensors at once. Expensive on a Mercedes, but the correct solution.

What happens is something like this. The sensors have an operating range. One sensor is at the left edge of the range and the other is at the right edge of the range or one or more of the sensors are slow to respond. The computer algorithm can't make all the readings work together. One scenario is that It misses once and then the sensor catches up and the computer adjusts.

The O2 sensors read good to the computer so it doesn't flag them as the problem. It does see the misfires and can flag that. I am guessing but I have also seen it before. I suppose if you have an OBDII scanner with readout or know someone with some skill in this area you might get a definitive answer.

 

Thanks for the response! Might be the cat because I've already replaced both 02 sensors a little under a year ago.

 

I was thinking of replacing the camshaft position sensor yet... but wouldn't a fault there cause all cylinders to run badly?

I cannot answer this from personal experience, but I do remember a thread on another Dakota site in which the OP said he had lost all the cylinders on one bank (I think he had a 3.9) and was getting a CEL, and we all threw out suggestions. Anyway, he followed up to tell us that he did change the camshaft sensor (CMP, also known on that engine as the distributor pickup coil), and he claimed that this fixed his problem. (As I remember, the CEL was NOT for his CMP.) I cannot vouch for any of that, since all I have to go by is what he posted on his thread, but seeing as you have already replaced the crank position sensor (CKP), if it was me I think I would make a clean sweep of those sensors (CKP and CMP), and if that doesn't fix it, I'd keep the original CMP for a spare. (And I confess that I have acquired a few spare parts using this method of troubleshooting.)

I'd say that a CMP shouldn't cost that much, but I do see that if you go MOPAR (and that seems to be what everyone recommends on these vehicles) it would run around $100 + tax + shipping which isn't exactly throw away.

2002 DODGE DAKOTA 4.7L V8 Camshaft Position Sensor | RockAuto

The prior post about the O2 sensors was interesting, and I'll file it for future reference in case I ever need it, but throwing all of the O2 sensors (does that engine only have two?) might not be super cheap either depending upon what brand you buy, and most everyone on these sites will tell you NOT to buy Bosch. I probably wouldn't go MOPAR either for those at around $151 pre-cat and $159 after-cat.

2002 DODGE DAKOTA 4.7L V8 Oxygen (O2) Sensor | RockAuto

 

Thank you. I am not trying to get the truck running perfectly, so I will most likely not drop the extra money on MOPAR parts, but thank you for the links.

 

This is how I deal with misfires. Both of your misfires on are on the same side of the engine. The right side bank or the passenger side. You need to check the fuel trims. Make sure your fuel trims are reading properly. You could have a vacuum leak. I would then read misfire data. Find where it’s coming from which you have done. Then verify your maf sensor and map sensor are working and the data that is correct. Then you can read the 02 sensor data and verify that the bank your misfire is on is operating as it should. If you don’t think it is then swap them side to side. While you have the 02 sensor out I would check the catalytic converter to see if it’s clogged. You can use a borescope. See if the misfire follows the 02 sensor before replacing it. Check spark and verify you are getting spark at the spark plug. After you know your plug/wire/coil is operational then you need to check compression. If compression is good then swap the injectors and see if misfire follows. If it does not follow then you need to check that your fuel pressure is good. After that inspect for mechanical damage in the engine. Things like valves sticking open or not opening fully, piston ring damage, piston damage, cylinder bore damage etc. Misfires can be tough to deal with but I never replace something when it comes to a misfire without absolutely knowing whether or not the part is bad. Sounds like you have basically rebuilt the top of this engine. Have you inspected the bottom end. Did you have coolant in your oil from the head gasket being blown?

 

Thanks for the reply I will look into that. I have not checked the bottom end yet. The oil did have coolant mixed in but I did an oil change immediately following the gasket replacement.

 

Make sure you don't have a head gasket leak. It can foul the plugs.

 

I just replaced the headgaskets a few weeks ago, as per the original post. Also, it is no longer burning coolant, so I believe the leak was fixed. Thank you