High RPM when idle and/or shifting gears

dodge
dakota

#1

Hello everyone,
I am in dire need of help. And if anyone could, I would greatly appreciate it. I bought a 2000 Dodge Dakota V6 privately and had noticed in the beginning, that my truck would just stall, while I was idle at red lights. So a friend of mine fixed my idle for me. Every once in a while I would notice my RPM going up, for no reason.
A few weeks ago I was in an accident. A guy pulled out of a parking lot onto the main street and hit my truck’s tire and totaled his car. My truck was seemingly fine. I do not know if this is related at all to the accident, but my RPM is consistently over 2000 now. Usually runs at 2500. Even though it’s not detrimental to me now, the truck is extremely loud, even when idle and whenever I shift gears, the RPM shoot up, as soon as I hit the clutch. Of course I am getting a lot of unwanted attention. But that’s not the main issue. I am running out of gas, fast. My engine light is currently on. And when I looked at my engine last time, one of my pulleys would spin, then stop and spin again, while the belt was going full speed. I have no idea what could be causing this. I know my power steering pump is leaking and my engine light has been on for an oxygen sensor previously. Are these things related at all?

Thank you so much for anyone willing to help!


#2

The idle problem might be caused by the idle air control (IAC). That part is an electric-operated stepper motor located in the throttle body, whose job is to set the proper idle speed. Those parts tend to get dirty and stick over time. So cleaning it is one place to start with high idle speeds. That part is controlled by the engine computer, which adjusts the idle rpm according to ambient and coolant temperatures. The IAC is also is involved with preventing stalling, in conjunction with the MAP sensor, during decelerations. It also adjusts idle speed for when the engine is loaded by some accessory, say when you turn the AC or headlights on.

The pulley slipping problem is something that must be addressed asap, but probably is unrelated to the high idle speed.

Before going to the trouble of cleaning the IAC, might be a good idea to have the engine computer diagnostics codes read first. If you post the codes here, somebody might see something else that could cause a high idle speed.


#3

Did your friend replace the idle air control motor or tamper with the throttle body? The idle air control motor should have been replaced.

You were probably looking at the hub on the A/C compressor, it is normal for that to cycle on/off.


#4

The sticky question is that we do not know exactly what you friend did while dinking with the idle problem. The original problem sounded like a faulty Idle Air Valve or a vacuum leak. I hope he didn’t play around with the throttle plate stop screw.

Maybe a vacuum leak has been created during the accident.

You have not stated which pulley is stopping and starting. Hopefully it’s not the harmonic balancer. Maybe whichever pulley you’re talking about is trying to seize up and the belt is slipping on it.

A lot of detail needs to be provided.


#5

Thank you for all the prompt answers! I will try to identift which pulley it is, in the morning.
When he tampered with my idle, he said he moved some type of screw. I believe he tightened a screw somewhere, because my idle used to be at about 400 RPM. That’s why my truck would stall.

I believed it was the throttle body at first and will try and see if there is a way for me to clean it. Could it be the faulty oxygen sensor, causing my truck to work too much? I will also try and get one of those readers, that can identify which problem I may have, so I can post the code here.

Thank you again! So much!


#6

I was able to post a video of the pulley.


#7

The hub of the A/C pulley in the video starts and stops via an electromagnet, that is normal.

Tampering with the screw on the throttle body is a bad idea, it will take some skill and patience to set the throttle body minimum air flow back to specs. The idle air control motor is most likely getting stuck at high and low settings causing the engine to race or stall.


#8

Good vdo for the lot of us w/not much AC experience to see how it works, but as posted above, that’s normal. When you get the diagnostic codes, post them here. Maybe somebody will have an idea. If the check engine light isn’t on, unlikely to be the O2 sensor. Continue to think it is the idle air control, possibly in combination with an ill-advised modification to a throttle body setting. Folks with a lot of car repair experience generally avoid messing with anything on the throttle body except stuff that is intended to be messed with, so if your friend is pretty car-repair knowledgeable, I doubt they messed with anything they shouldn’t.