My XC90 Volvo 2006 I thought was the PCV system so I had all the hoses there changed as well as the oil catch can but my engine li

Okay so I've had rough idle but even dies at times when it's cold even when it's warm and I thought it was my PCV system and so I had the oil catch can and all hoses changed but the engine light is still on and it still has a rough idle not as much but it does seem like it has more power accelerating the codes that pulled up before I change the hoses and catch can was something in the steering wheel and the mass air flow is low I have 18 days left what should I do what should I guess that is causing this rough idle and I just changed my mass airflow sensor just about a month ago
Experienced mechanics share their insights in answering this question :
There are more than ten principal causes of rough idle and that list doesn’t include potential mechanical faults such as uneven cylinder compression. By far, the most efficient strategy to resolve this issue is to request a rough engine idle diagnostic. The responding certified mechanic can scope the cylinder firing patterns, in each cylinder, and see, at a glance, if the problem stems from a few faulty cylinders or if there is a global engine management problem. Among the more notable causes of rough engine idle are a stuck open EGR (exhaust gas recirculation) valve, dirty fuel injectors, incorrect idle speed setting, vacuum leaks, incorrectly installed or damaged spark plugs, defective or clogged fuel pump, clogged fuel filter, failing electronic components such as the ignition control module, plug wires, coils, and spark plugs, a defective airflow sensor, and dirty oxygen sensors.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Fuel injector nozzles can become clogged over time, which can lead to a sputtering engine, slow acceleration and the car not having enough power. Fuel injectors can be cleaned if the problem is caught early, but as the conditions worsens, the injectors may have to be replaced.
A PCV (positive crankcase ventilation) breather system is designed to regulate hazardous fumes from your vehicle. As your engine runs, combustion gases escape from the combustion chamber, finding their way into the crankcase of your engine.
Spark plugs: Damaged spark plugs can trigger this error. If they need to be replaced, you can expect to pay about $200 per spark plug.
A clogged fuel or air filter can make your engine sputter and your acceleration lag because the engine is not getting enough fuel or air, respectively. The combustion chamber needs the correct amount of air and fuel in order to generate combustion efficiently.
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.
Common signs include oil leaks, excessively high idle, and a decrease in engine performance, power, and acceleration.
You can judge how serious an issue is by looking at the warning light. The check engine light can show up in two ways: Solid yellow/amber light: Indicates a less urgent issue. Flashing light or red: Indicates a severe problem that needs immediate attention.
A loose gas cap is one of the most common reasons for the check engine light to go on. Check that your gas cap is screwed on securely and that it`s in good condition. If you have a tank of bad gas in the car, your check engine light may come on.
The most likely issue is that a component is clogged. A clogged fuel filter is the most common reason, although a loss of power in your car could also indicate problems with the fuel pump or fuel line. Impurities or debris may be blocking the system, which causes the loss of power in a car.
Common Causes of a Failing or Degraded Engine

Low Compression. Dirty or Clogged Air Filter. Dirty or Clogged Fuel Filter. Bad Fuel Injectors.

A sputtering engine may just mean you need to have your fuel filter replaced. All vehicles have a series of vacuum hoses that create the fuel pressure. If one of them leaks or is damaged in any way, you will lose significant fuel pressure. The vehicle`s exhaust system can greatly impact the engine`s performance.
This is a common symptom of a plug or wire electrical current problem. Air or Vacuum Hose – Another common cause for engine vibration and power loss is when air or vacuum hoses come loose, begin to leak, or rupture. The three necessities for all combustion engines are air, fuel, and spark.
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.
Your engine fuel injectors can collect grime, dirt, and soot leading to an air-fuel mixture imbalance for your car. When this happens, you may notice poor performance, rough idling, and inconsistent gas mileage over time.
Installation position of the PCV valve on the cylinder head. In vehicles with turbochargers, power loss, rough idling, or whistling noises are indicators of a defective crankcase ventilation system, MAHLE Aftermarket reports.
Symptoms of a bad BMW CCV are: white smoke coming out of the exhaust, excessive oil consumption (burning oil), engine running rough and misfiring.
With lower crankcase pressure you prevent oil from pushing past the rings making it`s way into the combustion chamber. This makes for a cleaner, more efficient air and fuel burn.
If the check engine light illuminates, it will either blink or remain constantly illuminated, depending on the problem. A blinking light, or in some cars a red light instead of a yellow or orange light, indicates a problem that needs immediate attention. Either way, you should have the vehicle checked by a mechanic.
Bad Sensors

One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn`t working, the spark plugs won`t fire, keeping the engine from starting.

Connecting to an OBD-II Port

You plug an OBD-II scanner tool into it and, in most cases, out pops a code that tells you what the problem is. The scanner also allows you to clear the vehicle`s internal code, which is what triggered the check-engine light. Do that, and the warning light will turn off.

An indication that a vehicle is not receiving the right mixture of air and fuel is if the vehicle jerks or surges forward at high speed. Several components of the fuel or air intake system could cause this jerking or surging sensation to happen. Issues within these systems can also cause fuel economy to worsen.
If the fuel amount is too much or too little, the engine may begin to sputter. Your mass airflow sensor tells you how much air is in the engine. Just like the oxygen sensor, the engine will sputter if there is too much or too little air.
A Volvo engine stutter when accelerating is a symptom that shows an imperfect internal combustion in your engine. Insufficient burning inside the engine will make the car hesitates or jerks when driving. This could happen during acceleration, driving downhill, or gear change.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My XC90 Volvo 2006 I thought was the PCV system so I had all the hoses there changed as well as the oil catch can but my engine li
ANSWER : There are more than ten principal causes of rough idle and that list doesn’t include potential mechanical faults such as uneven cylinder compression. By far, the most efficient strategy to resolve this issue is to request a rough engine idle diagnostic. The responding certified mechanic can scope the cylinder firing patterns, in each cylinder, and see, at a glance, if the problem stems from a few faulty cylinders or if there is a global engine management problem. Among the more notable causes of rough engine idle are a stuck open EGR (exhaust gas recirculation) valve, dirty fuel injectors, incorrect idle speed setting, vacuum leaks, incorrectly installed or damaged spark plugs, defective or clogged fuel pump, clogged fuel filter, failing electronic components such as the ignition control module, plug wires, coils, and spark plugs, a defective airflow sensor, and dirty oxygen sensors.

Low oil pressure light comes on when idle. Check engine light is on as well. Both came on after getting an oil change 3 days ago.
ANSWER : It is possible that they put in the wrong viscosity oil. In rare instances, a defective filter will also cause low pressure. If there is too much oil, it will aerate and cause low pressure. Be sure the oil level is really not above "max". The P2187 code will appear if the oil fill cap is not tight but it will also appear due to a myriad of causes because that code only "generally" identifies a lean running condition. Consequently, numerous parts would have to be tested including the O2 sensor, gas cap seal, manifold air leaks, any vacuum leak anywhere including PCV and EVAP systems, exhaust leaks, and fuel system faults such as failing fuel pump, clogged filter and more. Since the car has relatively low mileage, you would not expect a failed oil pump, although the pressure sensor (or switch) could be bad. However, the occurrence of the oil pressure warning light is quite coincidental to the oil change, thus I would suggest bringing the car back and asking them to redo with a new filter and double check the viscosity of the new oil that they use. If the problem persists after that, you will have to test actual operating oil pressure (at idle for instance) as well as the oil pressure switch. Finally, if the oil pressure warning light comes on continuously, unless the warning circuit itself is malfunctioning, that means the oil pressure is too low to operate the engine without damaging it. Anytime the light comes on for more than literally an instant, you should shut down the car and thus an issue like this obviously has to be repaired.

If you’d like, a YourMechanic certified mechanic can come to your home or place of business to inspect the vehicle and perform an oil pressure light is on inspection to diagnose the vehicle and suggest potential repairs.

Check engine light and oil light comes on before oil change?
ANSWER : Hi There,
As you may know, these lights are designed to come on at specific mileage intervals that are preset by the factory. When your mileage exceeds a certain amount relative to the last oil change, this will trigger the lights to come on. Typically this will include the oil light and the check engine light as there are also other basic service items that are checked during oil changes. I would recommend obtaining an owner’s manual for your car if you do not already have one. This will usually indicate the specific service intervals and recommended maintenance items for your vehicle at the various mileage intervals.

The tire pressure monitor will also come on when the air pressure in the tires has reached a specific threshold relative to the tire design specification. Tire pressure is also impacted by the outside air temperature. For every 10° drop in air temperature outside your tires will lose about 1% in PSI or inflation. As you may know, as the temperature of the air changes the density of the air changes as well causing the tire pressure to be impacted by this. When this happens, the sensors in the wheels will detect this change in tire pressure and cause the tire pressure light to come on. Aside from replacing faulty tire pressure sensors, another way to help prevent this type of fluctuation in tire pressure is by the use of Nitrogen in your tires rather than regular air. As you may know, air is approximately 78% Nitrogen, 21% Oxygen and the rest is water vapor and some other small concentrations of gases. Nitrogen is much less likely to migrate through tire rubber than oxygen. This will maintain your tire pressure much more consistently during large temperature fluctuations.

I Had my oil changed on 5/28/16. On 5/31/16 the check engine light came on. On 6/5/16 the low oil pressure turn off engine came on
ANSWER : Hello,

From what you describe it would not appear to me that something went wrong during your oil change.

If the level is correct on the dipstick and the engine runs and sounds okay, then it is probably something else.

A likely cause for a problem such as this can be a defective oil pressure sensor, or wiring.

Virtually all vehicles have a dedicated oil sensor that will monitor oil pressure of the engine and set off a warning light if it falls to low, in order to protect the engine. If the sensor fails however, it can send a false reading to the computer or gauge, and cause the warning light to activate by mistake.

I would recommend having the vehicle’s oil pressure sensor tested for accuracy, and if necessary the engine’s oil pressure to make sure that there is no issue with the oil pump or system of the engine, as unlikely as that may be.

I’d recommend having a certified mechanic inspect the vehicle for you, they will be able to check for these failures and diagnose your Check Engine Light in order to get your car running normally again.

Regards,

Eduardo
YourMechanic

The engine klunking and tapping, needs engine replacemet
ANSWER : The reason the shops told you to replace the engine is that they do not overhaul engines. They can only replace it for you with a remanufactured or used engine. An overhaul is a third option but would most likely not be as cost effective and may even cost you more since the labor and parts can be more than replacing it. Since you already had two shops say it needs an engine, then I would suggest having them both give you quotes on remanufactured or used one. Make sure to get the warranty in writing so you can see if a future failure is covered.

2006 BMW oil filter gasket keeps breaking and oil leaks from oil filter. Oil leaks only after starting car in morning. PCV valve?
ANSWER : Hi There,
It sounds like you may need to replace the oil cap o-ring. If you haven’t done this before there are two O-rings to replace; a small green one on the base of the filter cap stem and the large black one that seals the filter cap (which seems to be the one you are having issues with). The large O-ring sits in a small square-shaped groove that is at the base of the oil filter cap. It is very easy to not properly seat the large O-ring because the threads for the oil cap are quite large and will accept the O-ring if you are not careful. I would suggest having a professional from YourMechanic come to your location to take a look at your vehicle.

Just noticed a huge oil leak trailing my car. It seems to be coming from below the engine. I recently had my oil changed a month
ANSWER : You might have a problem with the oil filter leaking when you rev the engine and increase the oil pressure. This can be from a collapsed oil filter media or excessive oil pressure from the engine. I recommend having the oil and filter replaced using a good quality filter and have the oil leak verified to be from the filter. Make sure to not run the engine low on oil. If you are finding you do not want to drive with the leak, a mobile technician from YourMechanic can come to your home or office, and replace both your filter, and oil.

Check engine light refuses to go off after engine replaced
ANSWER : Hello there, you have a long series of issues going on with your 2013 Hyundai Sonata. If you keep getting a repeating oil light on than there is likely a fault in that system.

Since this fault has lasted after the engine was replaced it could be a oil pressure sensor, wiring harness fault, ECU fault, oil pump, oil strainer clogged, or low oil pressure.

To diagnose this issue properly you need a complete vehicle inspection to start from square one and identify the root cause of all this.