Why is My Car’s Engine Idling Rough?
Your vehicle’s idle is a good indicator of overall engine health, and if you find yourself with a rough idle, fast idle, or other idle issue then it is a good idea to troubleshoot the problem right away.
Sometimes the fix for bad idle is as simple as a tuneup as clogged air and fuel filters are common culprits. Below are some of the reasons your engine could be idling roughly, and what you can do to fix a rough idle:
- Vacuum Hoses. Your engine’s vacuum lines control a variety of things, and they can wear out over time. A worn or loose vacuum hose can easily cause rough idle. Inspect any hoses in your engine compartment for signs of wear or loosening and replace damaged or broken sections.
- Dirty Air or Fuel Filter. Check your vehicle’s maintenance record. When was the last time you changed the air filter? What about the fuel filter? Your engine needs the right mix of air and fuel to run properly, and if any of your filters are plugged up with dirt or debris then it will make your engine idle rough as well as reduce your fuel economy and performance. Not replacing your fuel filter can also damage your fuel pump, which is very expensive to fix! If you suspect your vehicle is due for a tuneup or filter change, book an appointment at Kelowna Nissan right away.
- Fault in Ignition or Electrical System. Many modern vehicles now use distributorless ignition, which requires less maintenance than a traditional ignition system with a distributor cap. But this doesn’t mean that you can get away without changing your spark plugs. If your spark plugs are fouled or the electrode is excessively warn it will cause problems with ignition that can lead to rough idle. You can remove a spark plug yourself to see if the electrode has deposits or is warn, or bring it in to us and we can see if it’s time to change your spark plugs. Be sure to check your spark plug wires for wear as this can also cause poor ignition. If your vehicle does have a distributor cap, make sure you change this too.
- Worn Timing Belt. If your vehicle has an interference engine (the clearance between the valves and the piston overlap), a worn timing belt can result in extreme engine damage. If your timing belt has jumped a tooth or is excessively worn, then you should bring your vehicle to an authorized mechanic as soon as possible. Check your vehicle’s manual to see how often your belt should be changed. Some vehicles use a timing chain as opposed to a belt, and in most cases this will not require replacement.
- Fault in Electronic Engine Control Systems. If your vehicle’s engine light is on and you are experiencing a bad idle, you can attach an OBDII engine code reader to diagnose what could be causing the issue. If you don’t have an OBD (In Board Diagnostics) tool, bring it in to our service department and we can scan it for you.
- Oxygen Sensors in Need of Replacement. Your vehicle’s O2 (oxygen) sensor tells the computer how much fuel to inject in order to have clean and efficient combustion. If your oxygen sensor is in need of replacement, your vehicle won’t run as smoothly and you will experience reduced gas mileage.
- Fuel Injectors in Need of Service. Dirty or partially plugged fuel injectors can cause rough idle as your engine won’t be receiving a properly atomized stream of fuel in the cylinders. Our fuel injector cleaning service will restore the performance of your injectors and improve your fuel economy while smoothing out your idle.
- Poor Compression. Poor compression is a sign that your vehicle’s engine is excessively worn and in need of ring or seal replacement. Compression is needed to ignite the air and fuel mixture in the engine, and poor compression will result in a variety of drivability problems as well as increased oil consumption.
- Dirty or Faulty EGR Valve. Your Exhaust Gas Recirculation (EGR) valve is an essential component of your emissions control system. It feeds heated exhaust gases back into your cylinder for more complete combustion. If your EGR valve is faulty, then it can cause rough idle. The solution is to replace or clean the EGR valve.
- Low Fuel Pressure. If your fuel filter isn’t plugged, but your vehicle still isn’t getting enough fuel, then your fuel pump may be at fault. A faulty fuel pump will make it more difficult to start your car and can also lead to a rough idle. A rough idle can be the first sign of a more serious engine issue, which is why you should book an appointment at Kelowna Nissan’s Service Centre for a fast and accurate diagnosis.