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Scott
Dodge Dakota
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3/21/2005
20:18:12
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 Subject: Rough idle on first start
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I've got a 2000 4.7 Sport with 48K miles. For a while I have noticed a rough idle upon starting the truck for the first time of the day. It will rumble almost to the point of dying until I give it a little gas and then it'll go up to about 1500 RPM on its own and back down to 700 or so. It may do this 2 or 3 times until it levels out and runs at a constant idle. It seems to worsen in warmer weather. Anyone else notice this quirk? Any suggestions? Thanks fellas!!
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D Brown
Dodge Dakota
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10/24/2006
19:29:48
| RE: Rough idle on first start
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I have the same problem with my 98 Dakota R/T 5.9
It seems to start up run likes going to die after sitting overnight. I give it a little gas it will idle up to where its supposed to. Someone mentioned to me about the fuel pressure may bleed down over night. It could be the idle control valve as well. It will be the next thing I replace.
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Darryl
Dodge Dakota
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10/24/2006
20:59:17
| RE: Rough idle on first start
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Same thing is happening to me on my 2000 Dakota 3.9. I have replaced the battery, spark plugs, wires, PCV valve, and the cap+rotor. Nothing has solved my problem so far
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Scott
Dodge Dakota
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10/24/2006
21:58:07
| RE: Rough idle on first start
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Finally some replies! I even forgot I posted this. You guys were really digging. Since then I have had the throttle body cleaned and Throttle Position Sensor replaced.....twice. This all helped but it will still do it on occasion.
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Kowalski
GenIII
10/25/2006
09:16:46
| RE: Rough idle on first start
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Ah, colder weather is upon us, bringing lower voltage to marginal or stressed batteries. At least 4 of you have posted on this same problem this week, and most will likely find the same solution. When the PCM doesn't see full voltage, one of the first things that happens is that it forgets the idle memory - and then has to relearn. This can cause stalling or low idle in our trucks. Upon relearning idle memory, they run fine, til the voltage goes low again.
D Brown - how old is your battery ? I'd be checking that before buying a new IAC.
Darryl - actually, you said your truck was ok for a couple days after the new battery - I just let you know what to check next in the thread you started on this.
Scott - sorry I missed your '05 posting - this is a well known problem to a few of us. Since its been going on for sometime, I'm wondering if something is draining your battery before that first start of the day ? For example, I had to hardwire my radar detector to a switched connection - the power plug and lighter socket stay hot in an '00 Dak (and likely many other years); if a device is left on it will run down the battery and could cause this. Another thing to check would be the underhood light if you have one - these are notorious for running down batteries. Failing that, you could have current draw somewhere else (the tach circuit in earlier gen Daks is well known for that) - then you'd have to start looking for current draw in individual circuits at the fuse panels. The warmer weather you cited is harder on batteries too.
Lead, follow, or get out of the way
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zzark
*GenII*
10/25/2006
17:40:07
| RE: Rough idle on first start
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My 94 has a rough idle for the first few seconds.
Using a scanner, I found the IAC was at step 56 or so before starting. When the idle settles down, the IAC step is 2.
So at some point, at shutdown or initial ignition power, the IAC is set to 56, and lets in too much air.
I don't know how to fix this initial step problem.
I just live with it.
zzark
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Kowalski
GenIII
10/26/2006
07:42:38
| RE: Rough idle on first start
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zzark - did you try cleaning the IAC ? Maybe its hanging up. What is the reading when the truck is fully warmed up ?
Lead, follow, or get out of the way
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zzark
*GenII*
10/26/2006
11:33:20
| RE: Rough idle on first start
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IAC is new and clean.
Engine warmed the step is around 2.
At some point, it seems it is purposely set to 56,
'cause I've seen that reading several times.
???
BTW, resetting the computer made no difference.
zzark
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Kowalski
GenIII
10/26/2006
15:15:13
|  RE: Rough idle on first start
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I suspected that - step 2 is open then; not closed like you were thinking. The IAC acts like a choke, enrichening the mix at cold start, then allowing more air as the engine is warmed up. I wasn't familiar with how the steps were numbered, but that's how it works. Maybe the butterfly itself is hanging up then; and not closing as much as it should. Does the throttle bore around the butterfly look dirty ? Or linkage pinched anywhere ? Did anyone screw with the stop for the butterfly ? A few things for you to check there.
Lead, follow, or get out of the way
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zzark
*GenII*
10/26/2006
16:58:42
| RE: Rough idle on first start
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Kowalski,
That's an interesting idea, I hadn't thought of it that way.
I'll check the other items.
Thanks
zzark
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eee
Dodge Dakota
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10/26/2006
20:09:47
| RE: Rough idle on first start
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2000 4.7 auto sport. 80,000 miles. Mine does same thing as first post. Has for a long time. Bought it new, seemed to start at around 40k miles too. I suspect it's just the fuel injectors, valves getting a bit gummed up. Only thing I've seen written about it is switching fuel injectors (ford motor sports) seemed to help/solve it. I keep mine in top condition (new plugs-10 to 15k) clean TB/IAC. ETC..
Runs best on brand new plugs, Tectron also seems to help.
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octane
Dodge Dakota
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11/01/2006
02:40:30
| RE: Rough idle on first start
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anyone know if those fuel injector cleaner addatives they sell at gas stations work?
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eee
Dodge Dakota
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11/01/2006
08:41:45
| RE: Rough idle on first start
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Chevron Techron is supposed to be the best. Pick it up at wal-mart, autozone, etc... Chevron puts it in their gas at the pump, too. From what I understand, nothing beats a professional cleaning (removing the injectors, cleaning them with a machine) but when I put Techron in, it makes a noticeable difference. Idles smoother, engine runs better.
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daddio
Dodge Dakota
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11/01/2006
09:20:51
| RE: Rough idle on first start
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try Seafoam and follow directions on the bottle. you won't be disappointed. found at most auto parts stores. best cleaner there is.
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DITTO
Dodge Dakota
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11/06/2006
20:56:01
| RE: Rough idle on first start
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Daddio is right on about Seafoam. I use it in all my vehicles and motorcycles and it's the BOMB
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GraphiteDak
GenIII
11/06/2006
21:08:21
| RE: Rough idle on first start
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Message:
Actually... the IAC needs to OPEN to allow HIGHER RPM at first and then it adjusts CLOSED until it reaches desired RPM's. Seems that they keep your RPM's HIGHER until it is warmed up.
It doesn't really CHOKE anything. Kind of the opposite as it just BYPASSES your (closed) throttle blade to allow some air to BYPASS as if you held the throttle open just slightly.
Since it's fuel injected, the PCM will adjust the fuel as needed. It also opens a little more at idle if the A/C compressor starts, or you turn the wheel with power steering.
If the IAC is sticking, it will do all sorts of goofy stuff. Either not open when it needs to, or actually adjust too far back and forth if it is sticky as it overshoots it's target RPM once it finally moves.
I actually took one apart on the Chrysler TB I got for my ATV. It isn't the biggest stepper motor and it takes like 256 steps to go from open to close. If it binds from being dirty it may actually receive several steps form the PCM before it starts to move again. About 8 steps to make one full revolution. Sensitive little buggards!
Taking it off the side of the TB and cleaning the crap out could help. Easiest thing is to just spray some cleaner in the TB as you slightly bump the TB open and shut again trying to get some cleaner to make it's way into the IAC port.
But of course, the LOW BATTERY problem will cause a similar problem for sure. Luckily it don't get very cold in Phoenix!
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israel rodrig
Dodge Dakota
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5/08/2011
23:32:29
| RE: Rough idle on first start
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Message:
I have a 2000 Dakota,v-6 3.9 it
has a rough idle,when I start it I
put new tune up the works what
could it be please let me know
anyone thanks....
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ya
Dodge Dakota
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5/09/2011
15:12:06
| RE: Rough idle on first start
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Message:
#1 Leaky injector or injectors
#2 Battery = Get it load tested
(note, load tested not just tested)
#3 Worn Dist. Bushing &/or Drive Gear
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Bubba
Dodge Dakota
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10/04/2012
13:08:16
|  RE: Rough idle on first start
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Message:
same problem!! i have a 2002 dodge dakota 3.9l v6! great truck i love it, but about 3 months ago i started it and it has a horrible rough idle at first like it wants to stall out? i replaced the throttle body intake gasket, plugs, wires, intake, and i put dry gas in it thinking maby it could have been moisture in my tank! when i took the throttle bodys off and cleaned them it ran awesome that day, but the next morning the same problem a cured, this truck is my only means of transportation, i cant have this motor take a dump on me, can someone please help. i need it to run smooth as possible, i baby the truck everywhere i go, but like they all sad, i have to lay into it to get out of my own way. i just turned 100000 miles, i always keep up on oil changes and regular maintenance, clearly this is a problem with alot of dakota/durangos and the rams. any suggestions please let me kno. also i noticed when i first start the truck the oil pressure rises and it runs like poop, and once it warms up the oil pressure falls, unless ofcourse im moving. i cant figure it out im stuck!! thanks keith!!
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richie
Dodge Dakota
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6/07/2014
13:12:36
| RE: Rough idle on first start
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Message:
I have a 01 dodge dakoda rough idle on start up and
when i shut it off and start it up it runs good
replaced intake/check vale spings/clean throttle
body/tune up/fuel pressure/ if someone has a better
idea or can steer me in a better direction (help)
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Clyde
Dodge Dakota
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10/09/2014
23:16:48
| RE: Rough idle on first start
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Message:
I have same prob w my 98 dodge dakota. Ill start then idles
real low then it fixes itself. After giving it gas it will idle low tgen
fix itself. Plz help. Clean throttle body but nothin. Also it dies
while goin bout 10 mph and continues to do so.
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