Car chokes when accelerating and when at a stop

ANSWER : Hi there. Based on the events you have described, finding another mechanic would be recommended. Your vehicle choking could be the result of a bad fuel pressure regulator, but I would not recommend replacing anything else until the vehicle is properly diagnosed. A restriction of the catalytic converter would also result in an overall lack of power, as the more you try to accelerate, the more it would hold back. A faulty fuel pump could cause what you are describing as well. The Check Engine Light leads me to believe the vehicle’s computer is recognizing the fault. Accessing the computer for codes may help with the diagnosis. I recommend having your vehicle’s choking problem properly diagnosed and repaired by a certified technician, such as one from YourMechanic.

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 : Hi, thanks for writing in. Sorry to hear of your difficulty with your 2012 Sonic. The good news is your Check Engine Light is on, so what means the fault has been "recorded" by the engine computer and diagnostic codes will be available to the mechanic to search for the fault. The codes don’t necessarily indicate which "parts" have failed but rather will indicate which systems are malfunctioning and causing poor operation of the engine. Individual components in these systems will then have to be tested by the mechanic. The traction codes may or may not be related to the issue with the engine, the poor acceleration, but those traction codes will have to be evaluated as well. It is possible there is more than one problem. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect your vehicle for you and download codes your car computer has stored, and make or suggest any repairs as needed.

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 : 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.

ANSWER : Hi there – based on the symptoms you describe, I suspect that either the throttle position sensor or the fuel pump (or fuel pump relay) are failing. The result is either incorrect throttle position reported to the engine computer, or inadequate fuel pressure to fire the injectors. I recommend a car is stalling 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.

ANSWER : Hi there. What you are describing is common with a CVT malfunction. This unique to Nissan transmission has experienced some hit and miss issues as you’ve described and can cause the type of warning lights and symptoms you’ve described. However, it is also possible that the CVT recall problem is not the root source of the other error lights. Specifically, the TPMS and ABS warning lights could be caused by an actual sensor failure; which may have triggered the CVT problem in the first place. As difficult as it is to wait without knowing facts, the best advice we can offer is to wait for the dealership to contact you about their diagnosis. Hopefully the factory recall is the source of your other issues and the repairs will resolve this problem.

ANSWER : You seemed to have three different potential problems. Symptoms such as these are not common or pattern symptoms, so giving advice about them here is not likely to help you much. Also, there isn’t enough information about your motor and transmission setup. There are two motors and one can be a hybrid, which changes the circumstances significantly. All your symptoms could be related or not. No way to tell without directly experiencing the issues.

Either way, aside from the sound, you have drivability issues that appear to intermittent. Intermittent symptoms can be challenging to reproduce, so be prepared for the technician to spend some time attempting to reproduce the problem. If these symptoms are indeed intermittent, you may want to wait until something is continually failing before having a technician take a look. It is a good idea to have someone spend an hour to see if something jumps out at them. But only an hour may not lead to the problem coming up again. We can spend many hours chasing intermittent problems with no diagnosis.

So the next time your car exhibits these symptoms, take note of the weather and temperature of the car. Is is fully warmed or cold? Do these problems occur after a long drive, in traffic, on a certain section of road? These details can often help us to reproduce the problems quicker. Are you climbing a hill, at a stop light, light throttle, at a cruise on the highway, etc. This is all good information that will help the mechanic when you are ready to have your car’s stalling issue diagnosed.