Okay guys, need a few suggestions. I have a 98 Dakota 3.9L and had some trouble in the past with stalling. Well that's gone, replaced PCM. As time went by on this thing over the last couple of months I have replaced a lot of parts cause the truck has 204K on it. Crank position, Cam position, MAP, Intake Air Temp, Coolant Temp, IAC. Plugs, rotor, cap, wires, typical tune up stuff since it's been over 60K since the last one. Oh yeah, Ignition coil as well a few months back. What's happening is a rough idle, even when cold. The first run in the morning, runs good except for the idle. The next time I get in the truck (say 10 minutes or so after being parked) is when it all starts. It will start to lose power sputter and sometimes like a pop. It will do this for about 10-15 seconds and then it's all normal again till I park and then the same thing. I can punch this thing and it just goes like nothing is wrong. I can drive for hours and everything is great, except for the idle. As soon as I park, it starts all over then clears up. Fuel pump was just replaced as I lost my fuel gauge and the age of course. I have a gauge hooked to monitor fuel pressure and it's 45 PSI constant so, I'm not loosing fuel. My thoughts are an intake leak, can't hear real well anymore so I'm gonna get somebody to listen for that but why only when I restart and drive it for 20 seconds or so after it's warm does this happen and then clears up. Valves or a bad cam but wouldn't it be always? Can injectors act this way? I guess my next thing is a compression test, what do ya all think? thanks!

This may need to be moved....sorry

 

Moving to the tech section. More visibility there.

 

Sounds like a finicky TPS I had the same problem replaced it no more problems and it was only 2 years old cheap part get a name brand or OEM.

 

Is the pop sound coming through the intake ?
If so mine was doing this and I removed the valve cover and found
that it was a lifter on its way out.

 

Going to replace that TPS as it is about the only sensor now that's original. I did put it on a scope when trying to troubleshoot this thing and it showed good as a nice linear line in a graph as it's rotated however, this is an intermittent problem and sometimes things are deceiving. The pop sounded like it's coming from the motor area but hard to tell when driving. At least I have some things to check out now....appreciate it. I'll post when I find the problem.

 

I'd wonder about a faulty IAC. But looks like you just replaced yours...did you use a Mopar part?

 

Faulty IAC is correct. It was replaced, defective. Just replaced again and engine idles a whole lot better however, still having that miss issue after shutting down and restarting after several minutes. This happens when it's warm. I can shut it down again for a few minutes, start it back up and in about 10 seconds or so is when it starts really running rough and almost feels like it wants to stall then, all of a sudden it clears up like nothing is wrong. I'm starting to think injectors now. Fuel pressure is steady at 45 when this happens so I know there is fuel available but it feels like it's not getting any. Another question I have and I will do some more research on this is whether or not a bad injector will cause the PCM to shut down the others? This is what it feels like. All the sensors are replaced and working, no codes. Thanks for ideas.

 

having same problems again with my IAC after a year, almost to date.
It was a replacement...

 

Consider replacing the TPS. I had issues too which I thought were caused by the IAC and they even improved slightly after cleaning it. However, it wasn't until I replaced the TPS that the issue was fully resolved.

 

I did everything guys. The truck has a lot of miles on it. Got it to perform almost where it needs to be. Used some sea foam in the gas tank and it helped a lot but every once in a while I can feel a little rock at idle and when I restart the engine after it's warm it gets a little funny for a short time and then everything is normal. Again it's improved as sometimes now a restart is completely normal. I did get my injectors today, plan on installing tomorrow and will see how it fairs. At this time all sensors were replaced cause some were original....it's amazing how long they hold up. At 204K the truck owes me nothing but I need to keep her just a few more years. Maybe a couple rear shocks and some stabilizer bushings, should be good to go for a while. Thanks for all the input, as always, enjoy this forum reading through various issues and how there resolved.