Q: Motor revs to 4000 rpms until it reaches 50 kpm then drop but idles perfect in park, what could cause this?

asked by on September 19, 2017

I start my car and it's idles really nice in park. Let vehicle run for a few minutes then put the car in drive and the rpms gage show the revs are at 4000 and stays at 4000 rpms until the speedometer reads 50 kpm. What could cause this to happen, I've never had any problems with my ecscape this all started last monday. Please help me to figure this out I'm stumped. I've checked all the fluids and they are good, now what?
My car has an automatic transmission.

Is the actual engine speed reaching 4,000 RPM or is the RPM gauge simply misreporting the engine speed? If the gauge is misreporting the speed, that is likely an electrical malfunction and to resolve it you can request an electrical circuit/component diagnostic. If, though, you are experiencing an uncommanded "excursion" to high RPM’s, that could be caused by a number of faults. In the majority of vehicles, engine idle speed is controlled by an idle control valve (ICV). The ICV valve can fail or a faulty or blown fuse in other electronically controlled systems can cause the IAC motor to malfunction, leading to a higher than normal engine speed. Failures in the ICV valve itself are often due to excessive carbon buildup in the intake manifold. Other possible causes of a uncommanded high speed include vacuum leaks, a malfunctioning throttle, cruise control malfunctions, and, rarely, a PCM/ECM malfunction. With regard to vacuum leaks, on a fuel injected engine a vacuum leak will cause a high engine idle as the engine’s oxygen sensor detects the extra oxygen entering the engine through the vacuum leak. The newly lean (too much air relative to fuel) status will result in the engine’s computer pumping in additional fuel, resulting in an abnormally high idle. A malfunctioning throttle system can cause both a high idle as well as an engine stall. A dirty air intake or cracked air intake tube is often the culprit. If you have engine speed "excursions" and you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine idle speed diagnostic - high idle and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

What others are asking

What does the “Fuel level low” warning mean in the message center?

While you can easily see the fuel gauge in your car, Ford built in a couple of additional safeguards to help protect you from running out of gas on the road. It’s all too easy to overestimate how much gas...

Replace throttle body 2010 ford fusion hybrid

Prior to replacing the throttle body, you should go through the Ford diagnostic procedure in the Factory Service Manual for this part to ensure that you do not replace a perfectly good part. The removal procedure is to first remove...

How do you turn off daytime running lights

Daytime running lights will come on and stay on all the time during the day and cannot be turned off unless the normal headlights are turned on. The daytime running lights should not stay on after the vehicle is turned...

My oil pressure low light comes oil and I replaced the sensor several times but it still comes on

Hello, thank you for writing in. Particularly having the check engine light on, the vehicle will have set off diagnostic troubleshooting codes that pertain to whatever component has set off the warning lights. You will want to start by having...

is it a temp sensor or bad head gasket?

A diagnostic would determine the root cause of the overheating. If the coolant level was low, and/or there was trapped air in the cooling passageways, perhaps related to the heater core repair, those faults themselves can cause overheating. If the...

2008 335xi oil pan gasket hell.....

Some external oil leaks MUST be repaired. That includes ones where the leak "drips" on a hot exhaust manifold. Such leaks are a fire hazard and, perhaps worse, a continuing health hazard because you are basically breathing burning oil as...

Car is making a knocking sound on passenger side. It started a few days again out of nowhere. It doesn't do it every time it start

I would have the knocking sound investigated and resolved first because it may be engine related and thus a priority. The relevant service to request is an engine noise diagnostic. Vibration felt in the steering wheel is usually tire and/or...

Heard loud noise, engine light turned on, the a/c stopped working and the car was very hard to drive. I saw a broken hose. Help!

Overheating can be caused by a number of issues. The hose blown off could be the cause as well as an effect. The engine could have begun to overheat before the hose blew off due to things like a stuck...

White smoke expelled from exhaust

The excessive fuel condition is from the exhaust regeneration system malfunctioning and should be diagnosed following updated diagnostic procedures for the check engine codes received. Follow technical service bulletin 09-10-02 for an updated procedures directive.

Related articles

A Buyer’s Guide to the 2007 Ford Crown Victoria
This This enduring Ford classic enjoyed a nearly two-decade run before being discontinued from the retail market with the 2007 model-year being the last. Ever-popular with law enforcement (for whom models continued in production through 2011), and senior citizens, the...
The Best Used Cars to Buy If You’re a Painter
If If you’re a painter, and you work for someone else, chances are you don’t care all that much about what you drive, as long as it gets you to and from work reliably. On the other hand, if you...
The Best Used Cars to Buy for Towing Light Loads
Towing Towing is tricky business and depending on the weight you’re dealing with, it really determines what vehicle is best for you. If it’s light loads you’re looking at towing, we’ve put together a list of the top five cars...