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Deon
Dodge Dakota
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2/22/2010
17:40:28
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 Subject: Hesitation on freeway @ 2000 RPM
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I have a 1998 V6 4.3 Automatic Dakota that has just about exhausted my patience:
The symptoms of the problem are that it idles a bit rough and sometimes turns off after stopping at a light (it does turn back on after is stalls out up to this point). It also has a strange hesitation that sounds like shifting (up/down) when on the highway stable at about 2000 RPM's.
As for diagnosing the problem and work performed thus far (by mechanic) is the following:
1)Complete tune up including plugs, wires, cap/rotor, oil/filter, PVC, air filter.
2) Replaced fuel pump.
3) Replaced brake master cylynder and complete system (needed it anyways).
4) Attempted reading any fault codes but none were registered.
Any trobleshooting tips to the above would be appreciated.
Thanks,
Deon
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Bob Lincoln
Dodge Dakota
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2/23/2010
08:10:58
|  RE: Hesitation on freeway @ 2000 RPM
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When you say you tried to read fault codes, did you get at least code 55 ("end of message"), or was there no communication?
Usually these signs indicate a faulty throttle position sensor, not always tripping a code.
I don't think it's a 4.3L engine. Could you mean the 3.9L V-6?
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Todd93/96Dak
Dodge Dakota
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2/23/2010
08:48:31
| RE: Hesitation on freeway @ 2000 RPM
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4.3 is GM. Dodge has the 3.9 V6 that year.
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Deon
Dodge Dakota
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2/23/2010
22:53:02
|  RE: Hesitation on freeway @ 2000 RPM
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Thank you for your response.
Sorry, I did mean 3.9L V6. It has 168K mi and was running well prior to this problem.
Actualy, since I posted my original message I replaced both the Throttle Position Sensor and Idle Solenoid (at rear of throttle body).
Also important to note, is that the Cruise Control is not activating but this may be a different problem.
The darn thing just seems to "JOLT" when cruising on the freeway.
Years ago, I had an erratic idle problem that was oddly enough, related to the thermostat of all things. This was weird! I had installed an aftermarket thermostat that was causing temperature deviations and would end up affecting the idle. The dealer found this problem.
I am in to this current problem over $1K and still can't resolve it!
Any help appreciated.
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fotodak
Dodge Dakota
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2/24/2010
07:51:06
| RE: Hesitation on freeway @ 2000 RPM
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Worn out timing chain/worn distributor drive gear.
3.9s do not have a timing chain tensioner and when the chain is worn it causes erratic valve timing, plus since the cam is out of time it throws off the injector sync.
Worn distributor drive gear/bushing makes it worse.
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Bob Lincoln
Dodge Dakota
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2/24/2010
08:21:08
| RE: Hesitation on freeway @ 2000 RPM
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You should have checked fault codes by now. Why did you replace the AIS? Shotgunning is expensive, as you now know.
Cruise control not activating may be a speed sensor problem, which could also cause they symptoms you reported. Check fault codes:
http://www.allpar.com/fix/codes/index.html
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me
Dodge Dakota
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2/24/2010
09:18:50
|  RE: Hesitation on freeway @ 2000 RPM
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Sound more like an oxygen sensor is bad. That would explain why your idle is erratic at stops and the OD shifting in and out. As for the cruise, the cruise buttons are notorious for broken and dirty contacts.
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daddio
Dodge Dakota
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2/24/2010
09:23:45
| RE: Hesitation on freeway @ 2000 RPM
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First things first, check for stored codes. Next check the TPS. You can do a simple test yourself and if you reply back I'll explain how.
Fotodak, I think the '98 3.9 should have a timing chain tensioner. I think that was a real problem on the earlier Magnum 3.9's.
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Deon
Dodge Dakota
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2/24/2010
20:29:51
| RE: Hesitation on freeway @ 2000 RPM
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Thank you all for the replies. And yes, shotgunning IS expensive, thank you.
Okay, I am all ears. From the replies I sort out the following possibilites based on this board's experience:
1) Worn out timing chain/worn distributor drive gear.
2) Speed sensor problem.
3) Oxygen sensor is bad.
4) Throttle positioning sensor. (Already replaced).
At this junture, I suppose to start with the most cost effective part to replace would be wisest. Probably leaves me with more sensors to replace first as mentioned above - Speed sensor and oxygen sensor. Will look in to getting these replaced.
The worn out timing chain seems debatable per above. Thanks.
Bob,
No recent codes reported to speak of; NONE.
Thanks for replies.
Deon
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fotodak
Dodge Dakota
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2/24/2010
20:40:42
| RE: Hesitation on freeway @ 2000 RPM
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Thahnks, dadiddio.
Good to learn more.
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yeah
Dodge Dakota
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2/25/2010
08:13:35
| RE: Hesitation on freeway @ 2000 RPM
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daddio I think they started the tensioner
mid year on the 97's,
Hey when you crank this motor over does it seem to
crank over faster and easier?
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daddio
Dodge Dakota
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2/25/2010
09:10:12
| RE: Hesitation on freeway @ 2000 RPM
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A simple check I've used before to check for a worn timing chain is hook up a timing light to it and watch the timing at idle. If it jumpos around the chain is usually worn enough to replace.
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hmmmm
Dodge Dakota
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2/25/2010
09:13:26
| RE: Hesitation on freeway @ 2000 RPM
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daddio if memory serves me right, With that test a
worn dist. gear would give the same results correct?
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mat
Dodge Dakota
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2/25/2010
16:40:19
| RE: Hesitation on freeway @ 2000 RPM
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yeah im having the same problem with my 97 dodge but im deeper in than you. mine jerks when it shifts into overdrive sometimes and idles erratically. so i had the transmission rebuilt and that didnt fix it and im in the process of checking all the sensors iv probably spent about 2300 trying to figure out whats wrong iv allready done plugs wires and cap and rotor i guess ill move to the fuel pump then check the timing chain she's got 215,000 miles on it
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Deon
Dodge Dakota
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2/25/2010
19:15:57
| RE: Hesitation on freeway @ 2000 RPM
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Mat and others,
Since I have already replaced the fuel pump and a bunch of other stuff as you have (see above), you may want to consider sensors listed on my post above "2/24/2010 20:29:51" (items 2 and 3):
2) Speed sensor problem.
3) Oxygen sensor is bad.
Also, most sensors are realativley cheap and easy to replace and should make primary targets (punn intended: SHOTGUN approach again).
Leverage off what I already did. The fuel pump DID NOT fix my problem. And by the way, the fuel pump parts and labor will run you at least $500.00 since it consists of an entire fuel assembly module (about $350.00 aftermarket). This is not to guarantee that we have the same problem but simply suggestive.
Is your cruise control operable? If not, we may be on to something here. Read my posts above.
Deon
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mat
Dodge Dakota
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2/26/2010
09:21:21
| RE: Hesitation on freeway @ 2000 RPM
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Iv checked the speed sensor i need to check some others but yeah my cruise works just fine on sunday im gonna check all the sensors then go from there
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mat
Dodge Dakota
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3/01/2010
10:21:50
| RE: Hesitation on freeway @ 2000 RPM
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so i check almost all of my sensors on Sunday at least the ones that could go bad with out making my engine completely stop. I found that my air intake temperature sensor looked burnt on the plug in and it was reading a little funny. iv order the sensor today so hopefully this fixes the problem for me have you fixed yours yet?
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Deon
Dodge Dakota
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3/01/2010
19:52:06
| RE: Hesitation on freeway @ 2000 RPM
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Mat,
Nope. The cruise control started working again so now I'm a bit confused (may be bad CC contacts or speed sensor?). I'm leaning towards speed sensor per Bob Lincoln's note (2/24/2010
08:21:08).
Let me know if the air intake sensor did the trick for you. I'll probably get to mine next weekend.
Deon
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mat
Dodge Dakota
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3/02/2010
08:18:25
| RE: Hesitation on freeway @ 2000 RPM
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well i wouldnt say the air intake temp sensor fixed it but it sure helped it out alot. but hell it might be a couple sensors gone bad who knows im just gonna wait and see now
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Deon
Dodge Dakota
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3/02/2010
13:53:53
|  RE: Hesitation on freeway @ 2000 RPM
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My "sputtering" problem continues to get worse on the freeway between 1500 and 2500 RPM. The guys at the auto supply store said it might be the MAPS sensor but it's over $100 bucks. The problem I have is that there are no returns allowed on electrical stuff.
Also, I just cleaned most of my under-the-hood connectors with contact cleaner and checked most ground connections just in case. Problems persist.
I also attempted to run the truck while the MAPS sensor was disconnected. Needless to say, it ran awfull and now I have a check engine light to boot! Even after I reconnected the MAPS sensor. So much for that.
Deon
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mat
Dodge Dakota
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3/02/2010
15:05:02
| RE: Hesitation on freeway @ 2000 RPM
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yeah if you disconnect a sensor the check engine light will come on so just disconnect the battery for a short time and it will go away also iv been testing my sensors with a volt meter to make sure there running right you can find all these procedures on how to do that in a hans repair manual
see i found out my air intake temp sensor was reading a little off so i replaced it so best to test than replace man
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