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Discussion Starter · #1 ·
Hello all. I noticed a new concern with my car this morning during my commute. Engine light came on and my RPMs started resting really high. Normally at 100km/hr (60mph) I sit around 2000 rpm now they are around 3500 rpm at the same speed. This new change of rpm also comes with a new higher pitch whine/whirring sound.

During acceleration I'll normally hit 3.5k and much higher rpm if I'm trying to get to speed quickly and this is the first one heard this noise.
I work in a heavy equipment repair shop so I've asked around for a code reader. I'll provide updates but since I didn't see this topic when I searched the forum, I figured I'd post something.
 

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If you are experiencing a rough idle or your RPM is running high when idling, then there are a variety of reasons for why this could be happening. It is not always easy to diagnose the cause because there are so many factors involved here.

1) Bad Spark Plugs
If you have bad spark plugs because they’re worn out or damaged, then it could be causing your engine to be idling rough. Remember that spark plugs are what send a current of electricity into the internal combustion chamber to ignite the mixture of fuel and air.
If the spark plugs are bad, then the electrical current won’t be sufficient enough for the ignition. This will cause the fuel and air mixture to burn inconsistently, which will result in rough idling engine.
2) Bad Ignition Coils/Wires
If your ignition coils or spark plug wires have gone bad, you will experience similar symptoms to having bad spark plugs.
Ignition coils, coil packs, and spark plug wires transmit a very high voltage to the spark plug which enables electricity to jump the gap. If the insulation on these components has worn away, they may be unable to produce a consistent high voltage output.
Any time the spark is unable to jump the spark plug gap, that cylinder has a misfire and no power is produced on that particular combustion stroke.
3) Vacuum Leak
ere are a lot of hoses that help deliver both fuel and air to the internal combustion chamber. One very common cause of idling rough is a problem with a vacuum hose in the vehicle. The hose could be damaged, loose, or worn out, creating a leak.
This could result in an abundance of air mixing with the gasoline, which would result in a misfire. Then, the result of that would be a car that is idling rough or having a higher than normal RPM.
4, Dirty Fuel Injector
Fuel injectors are the modernized way in which vehicles deliver fuel into the internal combustion chamber. The only thing is that these fuel injectors can get dirty or clogged after a while.
If you are not using gas additives or fuel injector cleaners on a regular basis, then there’s a good chance you’ll get a dirty fuel injector at some point. This will result in your car idling poorly. You could also see your gas mileage take a nosedive as well.
5. Bad Idle Air Control Valve
The idle air control valve (IAC or IACV) adjusts the amount of air that is allowed past the throttle body while the throttle plate is closed. This regulates the engine idle speed and allows idle to remain constant even if you switch on the air conditioning or turn on your headlights, both of which put more load on the engine.
If the idle air control valve did not compensate for these, the idle speed would drop when certain accessories are used. In severe cases, the engine may even stall.
The idle air control valve is most important on a cold startup. Problems with the idle air control will be most obvious during this time.
6. Incorrect Cam Timing
Have you recently replaced the timing belt on your engine? If the timing belt is loose or off by a tooth or more, the engine will likely end up with a rough and lopey idle, if it runs at all.
When the valves are not timed correctly, the intake and exhaust valves are open when they shouldn’t be, which reduces compression and causes the combustion gasses to travel where they shouldn’t on that particular stroke.
Have you recently replaced the timing belt on your engine? If the timing belt is loose or off by a tooth or more, the engine will likely end up with a rough and lopey idle, if it runs at all.
When the valves are not timed correctly, the intake and exhaust valves are open when they shouldn’t be, which reduces compression and causes the combustion gasses to travel where they shouldn’t on that particular stroke.
7. Incorrect Ignition Timing
While cam timing is mechanically controlled by a timing belt or chain, ignition timing is controlled by the ECU and the distributor. Some vehicles have a crank or cam angle sensor instead of a distributor that can be manually adjusted to advance ignition timing in much the same way.
If ignition timing is incorrect, the car could run rough and often try to stall. You should be able to check your own ignition timing using a timing light. The procedure is different for every vehicle, so check a repair manual if you’re not sure how to do this yourself.
Things to Remember
Your engine should normally get to around 700 RPM after you start the vehicle, depending on the model. If your idle is way off and you have one or more of the problems listed above, then you will want to diagnose the issue right away.
The cost of the repair or replacement job will depend on what the cause was. If you take your vehicle to a repair shop soon, then your engine should be okay.
But if you’ve continued to let it idle poorly for too long, then there could be irreversible damage to the engine. This in turn could cost you thousands of dollars in repair or replacement costs. So, don’t wait for this to happen.
 

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Discussion Starter · #3 ·
For clarification, the high RPM does not occur at idle. It's only at highway speeds and the code we got from reader explains further.

I put a code reader on it and the only code that came up was P0730 - Incorrect Gear Ratio.
Probable causes:
Transmission internals or transmission control module.

In my case it's likely the module since the transmission isn't slipping and acceleration/deceleration feels normal. Even the higher rpm doesn't give it the increased perky response feeling I normally would get.

Other forums that discuss this code often include other codes and a few times the description of the problem is that the transmission is slipping so my conclusion thus far is the module. I've called the dealership to get a quote on a replacement w/ the work.

I'll update the title if I can.

Car is:
2011 Dodge Caliber SXT Sport 2.0L w/ CVT
Just rolled over 190,000 km
 

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Discussion Starter · #5 ·
I never have... The dealership I take may car to for oil changes insisted that I didn't need to.
 

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Maybe you could have that fluid replaced first - should be changed out about every 80,000 miles (≈128km).

Ignore your dealership and [customer] request that it be done (by them). All fluids eventually get old.

There may also be TWO filters for the transmission; the one everyone knows about, and a second one that clogs up and causes an over-temp problem. I’d suggest having them both replaced as well.

Once you have clean fluid that’s at the correct level (with new filters), then you can figure out if something expensive needs to be addressed.
 
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