I posted a while ago about my '02 Dakota 3.9L V6. I'll say I love this truck, and have had minimal issues with it since I bought it in September 2022. I was having issues with it starting and it turned out the ECU/PCM was shot so I installed a new one and it seems to work pretty well. I did not get it programmed, and the reason I didn't get it programmed was because I would have to take it to Dodge and when I called to make an appointment the guy said "if it's running and the engine light isn't on, it's fine" So I never paid the $175 to get it programmed. Cut to, I was having issues with it in idle since I bought it, when I put it in reverse or I'm at a stop light, it tends to have a pretty rough idle and then it just stalls out. Once I restart it, I have to pretty much floor my foot to the ground to get it to actually move forward, and even when I slam my foot to the ground, it makes that sound like I'm out of gas even though I'm at 3/4 of a tank. Before I did the computer in Dec, '22, I switched the crankshaft and camshaft sensors, IAC sensor, fuel pump relay, and spark plugs and cables. New oil change maybe 1.000 miles ago. I personally think it's the fuel pump/fuel filter(same assembly) or it's a valve or vacuum issue. And I noticed when the AC is on, the idle is a LOT more rough than when the AC is off. And it almost seems as if when I have the AC on and I'm on the highway, it's like struggling to breath. I'm not sure how to explain it, but I really don't have the money to fix it right now, and it's my daily. I've tried Lucas fuel system cleaner and even a better grade fuel. Nothing is working, I don't trust the local mechanic, and I think I can do it myself, but either way I need it fixed ASAP. Please, any help/advice would be greatly appreciated.

 

How is your fuel pressure? Last time you changed plugs/wires/cap/rotor? What plugs are in it? Over 200K miles? Have you done a compression test??

 

I have not done a compression test. And when I replaced the spark plugs I did the distributor cap, all new cables. But on Tuesday I took it in to my local guy to have him take a look at it and see about the check engine light. He changed the throttle body position sensor, he changed the Idle Control Sensor, and the cooling temp sensor. None of those things had anything to do with the issue.

So he pretty much just ruled out anything with the throttle body, at least in my opinion. Which just leaves the fuel injectors and the fuel pump. And the last time I was faced with a coin flip, I made a judgement call and replaced the computer and that ended up doing the trick. This time I made another judgement call and told him to replace the fuel pump assembly. He had me sign a waiver saying that if this doesn't fix the issue he is not liable, which I was okay with because like I said this is what I thought the issue was originally.

 

What plugs did you have installed?

 

I think it was a local shop, whatever the step up from the cheapest brand was. But it was reading a misfire on cylinders 1/3/5 before I switched them and the code cleared after I put the new ones in, so I don't think it's the plugs/cables/cap

 

Does it run ok when you first start it, then start running worse after it runs for a few minutes?

 

Yes it runs when I first start it. The mobile mechanic that came to my house on Monday actually replaced the bank1 sensor1 O2 sensor, and that actually did the trick. Funny how a little $50 sensor could cause such a massive issue. It's also interesting that I replaced that sensor back in November of last year, and it must have just gone bad. Not really sure what happened but she's running good now.

The mobile mechanic did recommend that I replace the ignition coil as well, and he said that should make her run even more smooth.

 

What brand sensor did you install last year?