Rough idle when it is hot. When I start it when it is cold, I have no issues.
I have a Ford Explorer 2006 that has a rough idle when it is hot. When I start it when it is cold, I have no issues but If the car is hot, the rpm will increase and decrease and car may stall. If I leave it like 1 hour, it starts normally. No other issues at all. No check engine light. I cleaned maf sensor and T-body and replaced fuel filter and spark plugs but did not help. Please advise. Thanks
My car has 170000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi Ghary,
What you are describing sounds like an ignition coil that is beginning to fail. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.
What you are describing sounds like an ignition coil that is beginning to fail. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common reasons a Ford Explorer has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil. Search our network of RepairPal Certified shops near you to speak with a technician about your issue. Oops!
The most common cause of engine sputtering are issues with the fuel system. These can range from bad fuel filters, fuel pump issues, or fuel injector issues. The other possible source of the problem would be due to poor ignition – think spark plugs or ignition coil problems.
Worn and damaged tires can throw the Explorer off its game
Whether your wheels have lost a little tread, need to be re-balanced, or are completely busted, that can cause that tell-tale shake. A maintenance shop can usually balance those tires, or align them for a more even ride.
What is code P0174? The Diagnostic trouble code (DTC) P0174 indicates `System Too Lean (Bank 2).` The P0174 engine code indicates that the air-fuel ratio in your vehicle is too lean. Before the gas in your car can combust and power your vehicle, it must first combine with oxygen.
Causes of a rough idle. Many different problems could result in a rough idle for your car or truck, including: dirty fuel injectors, clogged air filters, bad spark plugs, and a variety of exhaust system issues.
A rough idling engine can be caused by spark plugs or spark plug wires. Spark plugs use the electrical current received from ignition coils to ignite the air/fuel mixture within the combustion chamber. A plug that is damaged or installed incorrectly can result in fuel being burned at an inconsistent rate.
Any unusual shaking or vibrating forces coming from the engine is cause for concern. It could be something as simple as old spark plugs producing an uneven power delivery, it could be something serious like worn or broken engine mounts, or it could be even more serious in the case of internal engine damage.
An engine that is hesitating to accelerate is most likely dealing with a fuel/air mixture that is too lean. Engine`s that are running inefficiently will begin to show signs like hesitation which will only become worse over time.
The Ignition System
The shaking occurs as your truck`s engine struggles to remain running while at idle. A few common causes within the ignition system are: Engine Misfires. Faulty Spark Plugs.
A loose or disconnected air hose or vacuum hose can cause quite a bit of violent shaking and vibration in your car`s engine. To correct the problem, simply look for any loose or disconnected hoses and reattach them and replace them as needed.
Too much fuel and/or too little air results in the engine running rich setting a P0172 trouble code, while too little fuel and/or too much air results in the engine running lean resulting in a check engine light for the Ford P0171 code.
P0171 is triggered by the engine bank 1 “upstream” oxygen sensor and P0174 is triggered by the engine bank 2 “upstream” oxygen sensor. The oxygen sensor alerts your system when the condition is too lean meaning there`s too much oxygen in the exhaust.
A PCV valve that`s stuck open will allow too much air to enter the intake manifold, leading to a leaner idling fuel-air mixture. Stuck closed leads to a build up of pressure in the crank case which creates a variety of oil leaks! And this in turn can lead to a range of issues, including a rough idle.
How to fix it? Cleaning or replacing the fuel filter and adding a fuel injector cleaning treatment to the fuel tank should take care of clogged fuel injectors. If the rough idle persists, it`s time to take your car to an auto repair shop.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
Do you hear a sputtering sound when you turn the key? This sound is a tell-tale sign that your battery isn`t getting enough charge and, consequently, isn`t sending enough power to the rest of the vehicle. This sound might be subtle at first, but as time goes on, the sputtering will get louder and longer.
Worn ball joints, shocks and struts, and rods can cause many vibrations to develop quickly. You may even have problems with your car`s brakes. Check to see if the vibration is only present when you press the brakes as you attempt to slow down or come to a complete stop.
In some cases, a misfire will cause your engine to run rough enough that you feel a noticeable shake. The check engine light will pop on, and it may even begin to flash.
What could the problem be? There are a range of reasons why your car is juddering when you accelerate. Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
This hesitation while accelerating can be the result of a number of issues, including something like a clogged fuel filter or even a broken fuel pump. Sometimes, something could also be wrong with the transmission.
Any unusual shaking or vibrating forces coming from the engine is cause for concern. It could be something as simple as old spark plugs producing an uneven power delivery, it could be something serious like worn or broken engine mounts, or it could be even more serious in the case of internal engine damage.
Simply put, a rough idle describes an engine that is not firing consistently when your vehicle is in park, with no gas applied. Most vehicles idle between 600 and 1,200 RPM and should hold their idle speed.
Any unusual shaking or vibrating forces coming from the engine is cause for concern. It could be something as simple as old spark plugs producing an uneven power delivery, it could be something serious like worn or broken engine mounts, or it could be even more serious in the case of internal engine damage.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Rough idle when it is hot. When I start it when it is cold, I have no issues.
ANSWER : Hi Ghary,
What you are describing sounds like an ignition coil that is beginning to fail. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.
What you are describing sounds like an ignition coil that is beginning to fail. Ignition coils are coated with a varnish-like insulation that becomes brittle over time after being stretched then contracted repeatedly The insulation develops small fractures that open when heated and close when cooled. When open, they allow shorting of coil windings and decrease or eliminate the coil’s ability to function. This type of temperature cycling happens because every time you shut the engine off, the fan stops running, the coolant stops flowing and the temperature under the hood rises. Every time you start the engine again the coolant flows, the fans turn on, and the temperature drops. When this heat dissipates and is absorbed under the hood, it is trapped causing this cycling effect. Components that contain heat sensitive materials include parts like coils, injectors, igniters, and some sensors. Any of these may be potentially subject to this same kind of heat problem which can be very difficult to trace. I would recommend having an expert from YourMechanic come to your location to take a look at your vehicle.
My air is blowing cold-hot-cold-hot-cold-hot…
ANSWER : It is possible that you have a leak in the AC system. There are pressure switches that will turn off the compressor if the pressure is too high or too low. The low refrigerant level could cause the AC compressor to cycle on and off. If you would like to have this done, a certified technician from YourMechanic can come to your car’s location to diagnose the AC system and make the correct repair.
Fuel pump engages. Batery good, alternator good volts, jump start helps when wont start. Temp does not matter. Intermittent?
ANSWER : Hello. Thank you for writing in. There are several reasons your vehicle may only start when jump starting. The first and most common is a build up of resistance that is causing you to need a boost of voltage to get the engine started. This may be due to poor battery cables, a bad ground connection, a poor starter solenoid, and a couple of other issues. The first thing you want to do is perform a visual inspection of the starting system. Make sure there is no corrosion build up in the battery cables. You can also check the resistance across these wires and make sure you have a solid connection between components. You then want to make sure the starter solenoid is doing its job. It is responsible for taking the small amount of electricity sent by the ignition and turning it into a huge electrical charge that is strong enough to push over the engine with the help of some gear ratios in its favor. Do some more testing, and stick to the basics before assuming its something seriously complicated.
The car idles rough and is shooting out codes p0017, p0016.
ANSWER : Hello. This is a common problem with the variable valve timing solenoid on this engine. I have changed quite a few of these due to failure. I always start by checking the codes and testing the solenoids and the connectors as some of the time the connectors fail and have poor connections. There have been a few times that I have seen these codes due to low oil or the wrong oil and from the camshaft actuators failing, but most of the time it is due to the solenoids. If you are planning on having this fixed, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair the rough idling issue for you.
My car isn’t starting, it’s really cold out. I was wondering how can I start it with this cold weather
ANSWER : Hi there. Given the description of not being able to start your vehicle, when it is cold and jump starting the vehicle without any problem. This leads me to believe the battery does not have enough cold cranking amp capacity. The engine needs to turn over fast enough to start. This may be nothing more than a weak battery. I recommend having this confirmed by a certified technician from YourMechanic.
While driving defroster set to hot blows hot air as it should, while idling it is blowing cold air.
ANSWER : First, the coolant level should be checked to make sure the radiator is full. While the overflow tank may be full, the radiator cap must be taken off to check the level inside the radiator. If you find the level is very low, you have a coolant leak that must be fixed. If coolant levels are normal, an engine thermostat or heater control problem may be what you’re experiencing. Consider hiring an experienced technician like one from YourMechanic who can come out and take a closer look at your lack of heat concern to offer a more personal diagnosis.
My car idles very roughly on first start up of the day
ANSWER : The lean fuel mixture codes may explain everything. They frequently occur when there is an air leak in the intake system somewhere. Your engine has an Air Flow Meter (MAF) that measures the air going into the engine. The ECU uses this information to decide how much fuel to inject. If there is an air leak, or of the MAF is bad or dirty, air will get into the engine without being measured and so there won’t be enough fuel delivered. This will lead to poor idle and misfires. You can check under the hood for damaged or poorly connected hoses or air boots, but if you need some help with this you can contact Your Mechanic. They will send a technician to your home or office to check out your BMW and tell you what it’s going to take to solve your problem.
My car started idleing rough, vibrations soon as start car, vibrations soon as I accelerate, vibrations, rough idle bad
ANSWER : This sound like you may be having an engine misfire. Have the system checked and scanned to see if codes are present for an engine misfire. If it is, then a mechanic can check to see if a coil or spark plug has failed. You may have oil leaks in the valve cover seals that has caused the ignition to short out in the spark plug holes. A repair of your valve cover gaskets may be necessary, along with the other components that I’ve mentioned. I’d recommend having the vehicle looked at by a qualified technician who will be able to diagnose these misfiring symptoms and fix it accordingly.
