Q: Skipping engine, rough idle, shuts off during slow down & idle, overheating, white smoke from exhaust

asked by on February 26, 2017

Car overheats at slower speeds & idle, already removed thermostat, week ago it began issue where it will crank up but then rpms drop to zero & car shuts off. Have to rev engine up high just to get car in gear before it shuts down. Rides very rough now & feels like engine is skipping. Also has a lot of white smoke coming from exhaust & when you cut car off it makes this loud noise that sounds like an airplane

My car has 190000 miles.
My car has an automatic transmission.

Thermostat Replacement $141.88 - $613.47 Get a Quote
Radiator Replacement $327.11 - $1271.53 Get a Quote
Idle Control Valve Replacement $146.15 - $920.51 Get a Quote

Hi There, It sounds like you may have a couple of separate issues going on here. Overheating can be caused by a number of things such as low coolant levels, a faulty thermostat, a clogged radiator or a failing coolant fan switch. As you may know the coolant fan switch helps to maintain the proper coolant temperature by turning on and off at specific temperature thresholds. When this switch is not working properly, this can cause the fans to come on intermittently, all the time or sometimes not at all. When this happens you will notice a temperature spike and drop occasionally as the fan comes on and off. When your thermostat is not working properly or is stuck closed, this will not allow the coolant to properly circulate through the engine, which may cause the engine temperature to fluctuate erratically or in some cases just remain hot. You may also have a water pump that is beginning to fail. Water pumps often times will begin to produce a bit of a whining sound when they are starting to fail. A common problem also associated with this is the water pump may begin to leak around the water pump shaft due to the seal being damaged. In addition to leaking around the pump, you may have a leak elsewhere in the cooling system coming from one of the hoses going to or from the radiator.

The rough idle and shutting off at slow speeds may be caused by a dirty or faulty idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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

My heater blows out warm air instead of hot air when my temperature dial is turned as hot as it can go.

Hello there, warm air coming from the vents on your 2001 Ford Taurus will be caused by a variety of issues. The heating system for your vehicle and the air conditioning system are completely separate and likely unrelated. A low...

Car engine recently overheated 2006 Ford Focus

Hi there - yes, it is normal for the AC compressor to cycle on and off. If it is doing this frequently however, like every 10-15 second or so, this can be an indication that the refrigerent level is low...

My car is leaking antifreeze

Hello, thank you for writing in. Hoses are generally flexible and can take a decent hit. When you hit a pot hole and send the front of the engine downward, you are more likely to break something that is rigid...

2013 Ford Fusion Car won't start and has a clicking noise when I turn the key... what's wrong

It sounds like you may have a weak battery, a failing voltage regulator or failing alternator. The rapid clicking sound is the starter trying to engage the flywheel to turn the motor over. When the battery is too weak to...

Station wagon sputters and hesitates

It will depend on the the fault that is stored causing the service engine soon light to be illuminated. Based on the description, I would suspect either an input sensor to the engine management system, such as an oxygen sensor,...

No acceleration when I press the gas

Hi there. Typically when you have acceleration problem as you are describing it can range from fuel, ignition or transmission problems. If the fuel system is clogged with excessive debris or carbon deposits, it will create acceleration problems, as will...

Is engine replacement complicated?

This would be impossible to answer since the Crown Victoria never had these engines and adding the larger engine with unknown changes from one engine to the other. The motor mounting, exhaust manifolds, wiring harness and computers are all different....

why does my motor move side to side when the truck is running ??

An engine that moves side to side in the engine bay can be commonly caused by defective motor mounts. If the motor mounts wear out or break, they will not be able to properly secure the motor in the engine...

Dead cylinder

If there is a stuck exhaust valve, that head needs to come off for a closer inspection. I would look into the low compression on the other head first. Perform a compression test, but also a leak-down test; you want...

Related articles

Top Five Selling Cars in Colorado in 2012
Colorado Colorado offers a varied climate depending on where drivers are located. Those in lower elevations see plenty of sunshine all year, while those in the mountain areas can see as much as 300 inches of snow. Due to this,...
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...
The Top 5 Selling Cars in Connecticut in 2012
Connecticut Connecticut offers plenty of rain and its fair share of snow during the winter months, which means drivers need vehicles that can handle these conditions. Top selling vehicles in previous years have included the Toyota Camry, Corolla and the...