Car vibration while at a stop

ANSWER : Hi There,
It sounds like you may have a dirty or faulty mass air flow sensor. The problem this can cause may also be compounded when the engine is cold due to the change in air density in cooler weather. The mass air flow sensor monitors air intake as it is mixed with fuel prior to being injected into the motor. This sensor relays information about fuel and air temperature, air speed entering the motor and many other things to the ECM which uses this to make adjustments to fuel supply to the motor. A dirty or faulty sensor can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bit of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. I would suggest having a professional from Your Mechanic come to your home to diagnose and inspect your vehicle.

ANSWER : There are two principal possibilities: faulty motor/transaxle mounts, or an engine operating or mechanical condition including the possibility of a faulty harmonic balancer. To obtain a conclusive diagnostic, please simply request an engine vibration diagnostic and a certified Mechanic, dispatched by YourMechanic right to your location, will get this resolved. If you do need new motor/transaxle mounts, genuine OEM Nissan mounts are recommended in order to maximize the chances of resolving the problem. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : It sounds like you may have a dirty or failing 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.

ANSWER : Hello – I would be suspicious of an exhaust system hanger which has gone weak, and is allowing the exhaust to bump into the chassis at an idle. It is also possible that the fuel pump is wearing out, and the "chattering" that a worn fuel pump makes is transmitted through the fuel tank into the car. It would be easier to notice at a stoplight, but fades while driving as other road noise increases. I recommend a vibration and noise inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

ANSWER : Hi, thanks for writing in. I’d be happy to try to help. It is hard to definitively diagnose what the issue is. At first it seems like a transmission issue. Automatic transmissions are rather complicated and can do strange things when they malfunction. If not an issue with the transmission, you could also have a clutch issue. Always start by checking the simple components first. Check your transmission fluid level. Make sure your transmission filter is clean and debris free. When you have the transmission pan off, you can look and see if there are any metal shavings at the bottom. There is often a small magnet at the bottom of the pan designed to gather any metal shavings for a quick diagnosis. This is a sign of more serious transmission problems. Unless you have experience with automatic transmissions, it is not recommended that major repairs be done at home. I suggest taking your car to a transmission specialist for help.

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.

ANSWER : Hello, from what you’ve described it sounds like you are having several different issues. The starter should have nothing to do with it stalling, but it will have something to do with the car restarting if it doesn’t turn the engine well. The stalling can be from the distributor or possibly a computer sensor.

The scenario where you hit a car from behind may be from another problem, alongside with the idling of the engine. Without knowing the model and engine size of your car I can only say so much. I would suggest having a mechanic do a thorough check of the entire car to check the engine, brakes, and computer systems to see if the problems can be identified and repaired, or at the very least quoted.

ANSWER : Hi there – you may have 2 related events here, a coolant leak, and a problem with the heater system. The current issue may be air inside the cooling system, which can cause overheating, and a lack of heater function. The lack of heater function could have 5 causes: the engine is not getting up to correct temperature (center of the gauge) due to a malfunctioning thermostat, the heater control valve is not letting hot coolant into the heater core, there is a restriction in the heater system that is preventing adequate hot coolant flow through the heater core, the heater fan is not working to transfer heat from the heater core to warm air for the passenger compartment, or the air blend doors inside the heater are not working properly to route warm air to the desired vents. I would recommend a heater system inspection](https://www.yourmechanic.com/services/heater-is-not-working-inspection) by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.