After repairs, SUV stalls after deceleration and idles

ANSWER : Using a scan tool to access any stored diagnostic trouble codes (DTCs) may give you some direction on this. I recommend cleaning the throttle body. TAC (throttle actuator control) or drive-by-wire throttles are very sensitive to dirty throttle bodies. You may want to bring the car back to where you had the repairs done to see if they can find any mistakes that were made. If you would rather have another professional technician check this, a certified mechanic from YourMechanic can come to your home or office to diagnose and repair the stalling issue.

ANSWER : A number of components or faults can cause your issues. A vacuum leak can cause your issues. Depending on the vehicle, components such as the mass airflow sensor, throttle position sensor, coolant temperature sensor, and a number of others can be the cause. Since randomly replacing parts can get expensive as most electronic components are not returnable once installed, having a certified technician, such as one from YourMechanic, diagnose the stalling/surging is the best place to start.

ANSWER : Hi there. This can be caused by the issues that you mentioned or a number of other things. You need to make sure all of the connectors are making good contact. I would then need to know what codes are in the computer to know if this is a circuit issue or not. Most of the time, it is not the circuit but instead a vacuum leak.

If there is a vacuum leak, then the vehicle will act like this and the computer cannot control the idle. Most of the time it is a bad hose or an EGR valve that is stuck open. That is the most common cause for this. I typically remove the EGR to check it to feel the diaphragm on the bottom of it to see if it is moving correctly. If you need to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your car’s idling issue.

ANSWER : Hello. I would start by scanning the vehicle for codes and checking to see if all of the sensors are reading correctly. If everything looks good then chances are it needs a new computer. I have seen the computers fail on these vehicles over and over again causing the ignition circuits to not work correctly which causes the vehicle to run just like this. If you need to have this looked at, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the vehicle is running like this] https://www.yourmechanic.com/services/car-idle-is-rough-inspection

ANSWER : The first thing you should do is scan the engine and repair any codes. Have the fuel vapor system checked to make sure you do not have any problems with a leaking purge valve leaking vapor into the intake when the engine is not running and then leaks even more vapor when you start up the vehicle. If system is not leaking, then have the spark plugs replaced after having the throttle plates cleaned and the combustion chamber and valves cleaned. The valves may have some carbon build up on them that will cause low rough idle even stall cold. If you want to have this done, consider YourMechanic, as a certified technician from YourMechanic, can come to your home or office to diagnose the cold start and let you know what should be done.

ANSWER : Hi there. The fact you able to get the idle speed to drop by tapping the gas pedal, lead me to believe the high idle is due to a sticking accelerator cable. Another possibility could be, a faulty throttle body not allowing the throttle to return to the closed position. Proper diagnoses should be performed to avoid unnecessary repairs. I recommend having your vehicles high idle be diagnosed and repaired by a certified technician, such as one from YourMechanic.

ANSWER : Failures in the charging circuit (alternator, etc.) do not typically cause a rough idle. A faulty throttle position sensor and/or clogged fuel injectors can cause the engine to run roughly but those are just two among many, many potential causes of a rough running engine. What will help you is a rough idle diagnostic during which the individual cylinder firing patterns can be evaluated on a scope. Those firing patterns will allow the mechanic to see if perhaps there is "a" or a couple bad cylinders and also whether the engine is experiencing a fuel system versus ignition system problem and in which cylinders. On an engine with so many miles, 240,000 in your case, compression should be tested in each cylinder as wear in the engine could potentially cause enough imbalance, from cylinder to cylinder, to cause the engine to run roughly. You have to keep in mind that typically there will be multiple issues with an old engine, for example you could have dirty fuel injectors, a sticky EGR valve and fouled plugs due to the inevitable leakage from old valve stem oil seals, or any of a number of other combinations. The best thing to do, to see if you can get additional service life out of the engine, and you likely can, is to methodically and carefully go through the list of possibilities. YourMechanic certified technicians specialize in just that so if you set up a diagnostic, a technician will get to the bottom of this for you and give you repair options so that the engine can be restored to reasonable operating condition.

ANSWER : Hi there. The engine has a vacuum leak and is causing the engine to stumble down on the idle. Check all of the vacuum hoses and the brake booster for any leaks. The engine is rich for it’s not burning all of the fuel properly and may also have bad spark plugs. If you need further assistance with engine not adjusting the idle, then seek out a professional, such as one from Your Mechanic, to help you.