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Dodge Dakota throttle position sensor

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Comments

  • dustykdustyk Posts: 2,926
    Have you checked that the Idle Speed Motor is working?

    Regards,
    Dusty
  • dustykdustyk Posts: 2,926
    Which transmission do you have?

    How many miles on the vehicle?

    When was the last tune-up performed (miles)?

    Regards,
    Dusty
  • It started idiling fine and have done nothing to it.What does this sound like to you?Fuel filter?How do you check the idle speed motor?Thank you for the help.keevine
  • dustykdustyk Posts: 2,926
    If it started idling fine since the temperatures went up, it could be moisture in the fuel. Moisture can freeze, restrict the pump pickup, fuel lines, and the Fuel Pressure Regulator.

    You can make a cursory check of the Idle Speed Motor by placing the Mode Control knob (Heater/Air Conditioning Control) in the defrost mode. Your should hear the Air Compressor Clutch engage and the idle speed should come up at least 50 RPM (50-125 RPM is spec.).

    I would recommend checking the connections at the Idle Speed Motor and Throttle Position Sensor connectors for loose pins or signs of corrosion. Since throttle position sensors are a common failure item, you could replace it as a shotgun approach.

    Check for the presence of excessive oil sludge in the fill tube under the engine oil cap. Remove the moisture diverter by grasping the end and pulling straight upwards. You will or should see the opening on the right (passenger) side of the oil fill tube for the PCV valve. If this is clogged, it could cause the engine to idle too low. In cold weather this can be especially acute. The PCV valve could also be clogged from the gooey sludge freezing overnight, then after it warms the engine may idle fine after that.

    Check the various vacuum lines for splits or cracks. This can cause a loss of idle control.

    The Engine Coolant Temperature or Manifold Absolute Pressure sensors could be defective.

    Best regards,
    Dusty
  • Thank you for responding.I will start looking for problems.After reading your response you mentioned switching the heater to the defrost mode,well thats the only place it will work.Does that tell you anything different?Its not a big deal if it doesn't as long as it defrots my window.Oh I forgot to tell you,from the time I made the last response it stoped idiling AGIAN! Thank you again for all the help keevine
  • dustykdustyk Posts: 2,926
    Sorry for the late response.

    When the heater control is placed into a defrost mode, a signal is sent to the PCM which causes the Idle Speed Motor to advance slightly. This is to compensate for an idle speed drop caused by the increased load of the air compressor.

    If it idles fine in the defrost mode, you either have a defective Idle Speed Motor, or a PCM problem. It's possible the PCM might need a reset, although I think its more doubtful in this case.

    By connecting a DRB3 scan tool to this truck, a Dodge tech. can get a better idea of what's going on.

    Regards,
    Dusty
  • My 99 sport 4x4 cranks fine and runs fine until it warms up.Then it doesnt want to idle but its fine at high RPM's. 3.9 motor. Can anyone help PLEASE?
  • wvbigdogwvbigdog Posts: 1
    edited November 2010
    I've been searching for weeks online for an answer to this issue I'm having so I'll try here and see what I get for an answer since dustyk seems to be direct and to the point.

    My son couldn't make payments on his 1998 4x4 Dakota SLT with a 3.9 and auto and 104,000 miles, so I took it over figuring it would be good to move our boat from the shed to the ramp at Raystown Lake in PA (less than a mile). The issue he passed on to me though is a throttle issue. The throttle responds as it is supposed to when the truck is first started and until it warms up, then if you step on the pedal while in park or nutural the idle will roar to about 2800 rpm and very slowly back off to about 750 give or take. When I say "slowly falls" it might take 8 -10 seconds to fall back down to 750. In gear this is not evident if it's happening, but I have to think it could so I'm concerned...a lot.

    I've replaced the TPS since it seemed one of the cheapest fixes and the root of much discussion for idle problems. I think I did a pretty good job checking all the vacuum hoses; and they look good although I'm tempted to replace them just to be sure. I cleaned up the IAC and it's seat/port in the TB, and it tested ok using a 9v battery, but it might be sticking and it's the original, so I'm thinking it's another cheap replaceable item that probably will need replaced soon if it's not the root to the current issue thinking of the vehicle age and mileage.
    The dealer where he bought it was closed by Dodge in the sweep of taking away small town dealers this year, and I'm not real happy with the alternatives that charge 30% more just to component change and they really don't care what your name is as long as the money is green, so it hasn't been to a dealer shop for their opinion. Our local shop says it might be one of these sensors but without leaving it with him he can only guess (he is mostly GM by training).

    I'm not dumb under a hood or at least in the old days I wasn't ;) , nor afraid to get my hands dirty so I'm looking for possible answers and then I can change my own components without the hourly labor charge.

    Thanks for your help!

    Wvbigdog
  • I have a 2000 Dakota,181,00 miles, magnum 6 cyl engine;at below 30 degrees my truck starts and idles fine;after 10 miles or so,I notice some hesitation;if I take my foot off gas pedal and start to accelerate the engine falters then suddenly throttle up;this goes on for a few miles until I come to a complete stop.At no time during all this bucking and jerking does the engine light come on.
    When I take off again the vehicle is fine and runs all day long at any speed with normal acceleration and idle;once the truck sits all night it is the same problem the following morning unless the temps are above 32.
    I changed out the coolant temp sensor and have had a tune up within the last year with new plug wires installed.All other sensors on the car are original parts.
    Any suggestions? I would appreciate your insights..thanks ! Mark
  • dougdoug Posts: 7
    truck was taken to shop where 3.9 v-6 was diagnosed with faulty tps they replaced it and now idle speed is about 1000 rpm too high
  • I don't know much about engines, but my Dakota is having acceleration/idle problems, and the computer isn't showing trouble codes...problem has gotten much worse after replacing head gaskets & gasket on exhaust manifold. It's a V8, 4.7 liter, 2002 Dakota SLT with 4W & AW Drive. Prior to the head problem, it had a minor rough idle and appeared to want to die on quick stop in early morning after the installation of a new air filter system (which made a whistling sound), but after the heads were fixed, it idles rough & barely wants to climb a hill (like it's starving for gas/air). Repair shop says to drive it for awhile so trouble codes will register, or I can leave it at the shop for a couple of days. Since I don't know too much about engines, I'm hoping you experts can give me some ideas on what the trouble(s) could be (budget). It's got 109,476 miles on it. Plugs, oil, sparkplugs, and one of the O2 sensors were replaced when the head gaskets were replaced (no wharp/crack).
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