I know this question has been beaten to death. & I AM looking currently on this Forum and other for an answer. But figured I'd ask anyways while I continue looking...

99 Dakota 3.9 w/ ~110k on it. Reciently it started this Rough idle/Power issue. Here's what makes my scenario a little different from others. It only lasts for ~5 mins. Happens after EVERY start up, Warm or cold.

It starts right up Every time, no issue, no hard crank, fires up like brand new... It will run fine for the first 60 secs, then the engine will begin to spudder. It Idles rough and runs like S**t for a few minutes. Anything less the WoT & I have absolutely NO power, which makes merging into traffic a nightmare. After the ~5 Mins, the truck drive fine at any RPM & idle like normal (600-800RPM)

It does it in Drive, Neutral, Park. It hasn't yet dies durring the 5 mines. I want to resolve this issure before it gets worse & it gets too cold to work outside

So far, all i've done is:
Cleaned IAC (it was caked with black stuff) Still not sure if its working correctly, but it's atleast shiny now...
Cleaned TB (probable could of done a better job. Will try to clean again once i take a look at the EGR ports & valve.

Not sure what condition my plugs/Wires/distributor cap are in, but i dont see how they could be bad if the truck starts without issues.

EGR system cause this issue?
PCV? My catalytic converter? Any part of my fuel system? Vacumn leak?

What has me stumpt is the fact that the problem goes away after a few minutes. On another forum, someone suggested the fuel pump was going, & that it takes the pump a few minutes to build up enough pressure each time.

If anyone could give input to Atleast things i could rule out would be greatly appreciated.

 

Have you checked for codes? That's the first step. Most 99's won't do the key dance but you can try. With the engine off, turn it to RUN (don't start it), then OFF, then RUN, back to OFF, then leave it in RUN. Any codes will display in the odometer. It will say PDONE when complete. If it doesn't work, Autozone and Advance Auto will usually read codes for you.

Definitely check the plugs/cap/rotor/wires. Make sure the engine is mechanically sound before you go hunting. Wires can break down hot or have poor continuity cold. The gap could be bad on the plugs. There could be arcing under the cap, lots of things to rule out.

I'd be looking at the canister purge solenoid. It is disabled until the engine warms up and there is a delay on it when starting hot -- there should be anyways. It can cause rough running.

How's the battery? Check the voltage when you first start the truck and it's acting up. Dakota's HATE a low battery and will run like crap.

It does not sound like a fuel pump issue. You can rent/borrow a fuel pressure gauge to rule out the fuel pump. It won't take a few minutes to build pressure and you would usually starve for fuel at higher speeds.

A vacuum leak can cause problems. You can also rent a vacuum gauge to check. Most are NOT temperature dependent however. PCV wouldn't be likely.

A bad (collapsed) converter would usually cause problems more at higher speed. It wouldn't be temperature dependent.

Start with the codes. It's helps eliminate guessing.

 

Thx for the detail reply. It hasn't shown a Check Engine light, but for all i know the bulb could be out.
I'll take it a Autozone/wherever to get the battery checked & check for codes. The battery does look in rough shape.
Canister purge solenoid? Never herd of it. I'll do a lil research on that to see what it is/does & how to go about diagnosing it.

As for my spark system, if Any part of that were bad, then why would it go away after a few minutes?

1 thing i forgot to mention, this all started shortly after a bad flud in my area. I stupidly took my truck into 2ft deep water filled road to dick around in. If any water splash high up on my engine, could i have shorted out somethen? More specifically, my PCM?

 

Moisture may cause high voltage "leaks" on your distributor cap and wires. As the engine heats up it can dry them out.

Disconnect the battery then disconnect and clean the connections to the PCM. The PCM itself is pretty well protected from water. It would be the last thing I'd consider.

The canister is on the frame rail under the truck by the gas tank. If you went through that much water some may have been drawn into the system.

Also, there is no EGR system on a '99.

 

if your still having trouble go back and replace IAC with new, for the price and done right should last you another 10 ? years and can be eliminated in your check list.

 

Im gonna try to check/clean all possible culprits to my problem 1st. After that, my only options are to start replacing parts or just taking it in.

Well over the weekend i changed out my spark plugs. The electrodes on these were smaller then the tip on a pencil. I'll admit, im NO mechanic by any means, But i figured i was mechanically inclined enough to change spark plugs. Obviously not, cuz now my truck won't start. Are dodge's notoriously finicky? I took out the plugs, rechecked the gaps, all .040-.043 then put them back in & torqued to spec. ~20 Lbs? Changed my wires thinking i may have broke them when removing. Still nothing... WTF could i have possible done wrong? I bought a cap & rotor, but i was gonna change that after i was sure the truck still started after the plug/wire swap...

 

Oh 1 more thing, cylinder 2 (passenger side front?) I couldn't change that plug. The sleeve the plug sits in was bent/dented inwards so my socket wont fit around the plug. Idk what to do about that one... but the truck should at least start with 5 new plugs right?

 

The ignition systems can still act goofy because of one part, whether it be a wire, the cap and rotor, or 1 bad plug, so definitely get that one changed. You should be able to bend that sleeve back out without hurting anything, just be careful to to break the plug. Also double check that you go the plug wires back in the right place on the distributor.

I'd inspect the coil for cracks too if it were me as well as take the battery terminals off and give them a good cleaning with a wire brush.

 

I tried pushing the bump inside the sleeve back out be it didnt seem to budge, can i just cut it off?? The terminals are fine, that was the 1st thing i changed on the truck were the wire terminals.

 

You should be able to take the sleeve out be pulling on it with vice grips. They are "press fit" into bores around the plugs. I'd love to remove them on mine, but they are actually there for a reason, heat shield so the wires dont melt from exhaust heat.