Low idle problem
I just replaced my IAC control valve and the Alternator as well because of low idle issues. Unfortunately, Iam still having the same low idle issue especially at start up in the morning. But after the car runs a while it smoothes out and drives normal until I go to start it up again and then it Idles low for a few minutes then it runs smooth . What else could be causing this problem with low idle? Also when driving on the highway at about 60 miles an hour it feels like the car jerks back as if it's not in overdrive. Please help me figure out what's caising me this problem.
My car
Experienced mechanics share their insights in answering this question :
Hi there. If the idle control valve is good then the problem is typically caused by a vacuum leak or an issue with the throttle body. I usually check the engine for vacuum leaks first. It may be a vacuum leak in one of the hoses or in the intake manifold. The intake gasket is a common failure.
If there are no vacuum leaks, then I would test the throttle position sensor to make sure it is reading correctly. If it is also reading fine, then I would check the throttle body itself. If the bore or plate is worn then this will occur. If you want to have this low idle problem inspected, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.
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.
If your car hesitates when you try to speed up at a low speed, it`s likely because the air and fuel ratio is too lean. A lean air-to-fuel ratio means the gas going into your engine doesn`t have the right amount of fuel and air.
However, there are times when the fuel, electrical, and exhaust systems that provide smooth acceleration become dirty, damaged, or simply wear out and need to be replaced. When this occurs, it sometimes creates a hesitation in the application of the throttle or a “bucking” sensation.
Worn-out spark plugs or the electrical cables attached to them are one of the most common causes of cars stuttering. A deficient spark plug causes the engine to misfire, making your car jerk when you accelerate.
The most common cause of engine sputtering are issues with the fuel system. These can range from bad fuel filters, fuel pump issues, or fuel injector issues. The other possible source of the problem would be due to poor ignition – think spark plugs or ignition coil problems.
A common issue that leads to the engine RPM drop when upshifting is the clogging of the fuel pump filter. If cleaning the strainer didn`t help to eliminate the RPM drop, replace the fuel pump.
If you hear your car engine stuttering, then the injectors may not be providing an adequate amount of fuel. To fix this, you should clean the injectors on a regular basis. Using a fuel injector cleaning solution might eliminate the issue of the car jerking.
Dirty fuel injectors are among the most common reasons for why an accelerator becomes jerky. The dirty injector leads to your car losing power when you attempt to accelerate while at a stop and when you try to drive at a consistent speed. This is the result of an engine misfire.
The most common reason for a car jerk while accelerating is that one or more of your spark plugs may be going bad, which will lessen performance if the problem persists. If you think this might be the case, have a professional check them and replace them if necessary.
The most common signs of bad spark plugs include start-up trouble, rough idling, sluggish acceleration, declining fuel economy, engine misfiring, and engine knocking.
One of the main reasons why your vehicle could be vibrating at idle could be due to worn out spark plugs. When a vehicle`s spark plug is faulty, it can interfere with the air-fuel ratio leading to improperly firing cylinders, resulting in a misfire while idling. Replacing your spark plugs will solve this problem.
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. Spark plugs are an integral part of your engine.
The most common cause of engine sputtering are issues with the fuel system. These can range from bad fuel filters, fuel pump issues, or fuel injector issues. The other possible source of the problem would be due to poor ignition – think spark plugs or ignition coil problems.
A sputtering engine is a sign of a lean fuel mixture in the combustion chamber. This can happen if you have a clogged somewhere in the fuel system that impedes the delivery of fuel into the chamber. For example, your fuel filter or fuel lines might be clogged.
Worn-out Spark plugs
Getting a qualified mechanic to diagnose, clean or replace your spark plugs will help stop sputtering.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Low idle problem
ANSWER : Hi there. If the idle control valve is good then the problem is typically caused by a vacuum leak or an issue with the throttle body. I usually check the engine for vacuum leaks first. It may be a vacuum leak in one of the hoses or in the intake manifold. The intake gasket is a common failure.
If there are no vacuum leaks, then I would test the throttle position sensor to make sure it is reading correctly. If it is also reading fine, then I would check the throttle body itself. If the bore or plate is worn then this will occur. If you want to have this low idle problem inspected, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.
High idling, jumping while idling, idle air control valve code
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.
After replacing the power steering pump there was a low idle, idle screw is all out, running rich, and idle speed doesn’t change.
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.
Idles between 500rpm and 1300 rpm. Main concern is low rpm. Belt or pulley chirping mainly at low rpm Drives perfect but Idles bad
ANSWER : Hello. From what you describe it would appear that your vehicle may have more than one issue.
Belt chirping is usually caused by a worn belt or tensioner. If either component wears out the belt may loosen and chirp when the engine is started, or cold.
The low rpm low quality idle can be caused by a few different things. I would look at the idle air control valve, as that is the component that maintains the vehicle idle, and at any vacuum hoses that may be cracked or damaged, and possibly leaking. This is more likely for older or high mileage vehicles.
If you’re unable to pinpoint the issue yourself, consider YourMechanic, as one of our mobile technicians will be able to come to your home or office to diagnose your starting issue firsthand and make the necessary repair to your car.
RPM issue. Car can’t produce enough power. Idles low and caps at low RPM.
ANSWER : Hey there, thanks for writing in about your 2001 Nissan Sentra. It sounds like you may have a throttle position sensor issue or idle air control valve issue. If the catalytic convertor was not replaced, it could also still be related to that component. I suggest having a certified technician, like one from YourMechanic, determine the exact cause of your vehicle’s loss of power.
Very low idling during cold start, stalling engine, 2007 Toyota Corolla
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.
Rough idling when cold, would not idle when it warms up
ANSWER : Hello. It sounds like you have already changed a lot of parts on this. Most of the time, the issue is actually caused by a leaking intake manifold gasket. This is the most common issue on this vehicle. It leaks and causes a serious vacuum leak which affects the engine as you mentioned, but allows it to run fine at higher speeds or better once it is warm. If you are going to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose your car’s rough idling issue.
Rattling noise upon starting and then louder rattling at idle if load is placed on engine such as A/C
ANSWER : Hi there. Given your mileage and your maintenance of the idler pulley, your problem is likely worn/weak hydraulic lifters (or other valve train wear) or the timing gear set. Starting the engine briefly (less than 30 seconds) without the serpentine belt attached, will eliminate noises from all accessories if the problem is with one of them. I would recommend having the engine inspected in person by a professional so that the rattling noise can be diagnosed and properly corrected.
