When i change a/c temperature pass 3. The truck shakes, idles and shuts off.
When using the a/c…I can not go pass setting 3 without the truck shaking, idling and basically shutting down. Once, this happens I turn the a/c off and have to restart the engine. What causes this issue, what needs to be done and how much will it cost?
My car has 179900 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi there. Shaking with the a/c on can be caused by a number of reasons. The a/c compressor puts a lot of strain on the engine because the compressor is similar to being a small engine itself. When the a/c is switched on, the engine control unit should trigger components such as the idle speed/air control motor, to increase the idle slightly to compensate for the extra drag of the compressor. If that does not happen, then the additional drag can cause a low,shaky idle and even cause the engine to stall. It’s probably a good idea to have a professional mechanic come to your location and complete a vehicle is vibrating inspection, so they can isolate the source of this problem and recommend the right repairs.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
The most common reasons a Chevrolet Trailblazer has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
Any unusual shaking or vibrating forces coming from the engine is cause for concern. It could be something as simple as old spark plugs producing an uneven power delivery, it could be something serious like worn or broken engine mounts, or it could be even more serious in the case of internal engine damage.
The most common reasons a Chevrolet Trailblazer has a rattling noise are the ball joints, struts or strut mount, or a problem with the sway bar links.
Typically, the idle speed will be set at a value in the range of 600 to 800 RPM, but the exact value will depend on the number of engine cylinders and whether the vehicle is equipped with a manual or automatic transmission.
Many different problems could result in a rough idle for your car or truck, including: dirty fuel injectors, clogged air filters, bad spark plugs, and a variety of exhaust system issues.
What to Look For: A lousy temperature sensor results in rough idle during cold starts. Once warm, the problem may be less noticeable. Faulty Airflow Sensor – Like the temperature sensor, the airflow sensor helps your car know how much fuel to use, based on the amount of air in the engine.
What could the problem be? There are a range of reasons why your car is juddering when you accelerate. Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
The most prevalent cause of vibration is problems with your wheels or tires. The potential problems include improper wheel and tire balance, uneven tire wear, separated tire tread, out of round tires, damaged wheels and even loose lug nuts.
One common problem that will cause a rattle at idle is a failing hydraulic valve lifter. The lifters are small parts that open and close the engine valves, activated by oil (hydraulic) pressure.
The AC compressor can become worn over time, requiring replacement. The serpentine belt is connected to many of your car`s accessories, like the air conditioning, alternator, power steering pump, air pump, and more. This belt can become worn over time leading to poor tension and noises like rattling or squeaking.
Typically, engines idle at about 600-800 rpm. Older engines may go up to 1200 rpm or more while warming up. But if the engine is revving up while idling, even after it`s sufficiently warmed up, you might have a problem. High idle speeds waste fuel, cause extra wear and tear on your engine, and can be unsafe as well.
For regular cars, idle speed is typically between 600 and 1,000 rpm, just enough to keep the engine`s ancillary systems going, but not enough to move the car forward much.
Oxygen (O2) sensor
An oxygen sensor monitors and analyzes the amount of oxygen in a vehicle`s exhaust system after combustion. A dirty, damaged or malfunctioning O2 sensor (or sensors) affects the air/fuel mixture, causing the engine to idle rough.
If the engine stalls while idling or driving, the engine may be running out of fuel or not receiving enough fuel pressure to keep it running. The most likely cause of this kind of stalling would be a fuel pump that is not spinning fast enough or is intermittently cutting out.
Engine Misfires
Perhaps the single most common cause of rough idle comes in the form of a misfiring engine. As you may know, any automotive engine contains multiple cylinders. Each of these cylinders contributes to powering your car by combusting a mixture of gasoline and air.
One of the most common causes for a rough idle and poor acceleration is a dirty or bad throttle body.
A harmonic damper is a device fitted to the free (accessory drive) end of the crankshaft of an internal combustion engine to counter torsional and resonance vibrations from the crankshaft.
What might be causing this? A clogged air filter. If your air filter has become clogged over time, then your engine may not have the right fuel-air mix it needs to combust. This build-up blocks the flow of fuel, which is what causes juddering, misfiring and a rough engine idle.
One common cause of shaking while idling can be loose engine mounts. Engine mounts are the connections between your engine and your car — they keep your motor safely attached while dampening vibrations produced by your engine. When those connections wear out, you`re more likely to feel the vibrations.
Low automatic transmission fluid can cause shaking. If the shaking is accompanied by the check engine light, it`s time to visit a mechanic. Drivers of manual cars might discover their clutch master cylinder is the source of the shaking.
The most common reasons for your car to excessively vibrate are a problem with your tyres, wheels, brakes, steering, suspension, axle or engine.
What does a bad catalytic converter sound like? Often, a clogged catalytic converter sounds like a rattling noise is coming from under your vehicle and engine when you`re starting, idling or driving. Excess heat or damage in the converter can break apart the honeycomb materials, resulting in the rattling noise.
There is a rattling sound. A lax timing chain, or worse, a broken timing chain with loose parts within the engine, will produce a rattling sound when your car is idling. This rattling sound is typically most prominent while the engine heats up and disappears after some time.
When the spark plugs malfunction, they reduce the effectiveness of the engine`s cylinders, which then causes the cylinders to rattle. These unpleasant noises indicate that the cylinders are being overworked and will lead to further troubles down the line.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
When i change a/c temperature pass 3. The truck shakes, idles and shuts off.
ANSWER : Hi there. Shaking with the a/c on can be caused by a number of reasons. The a/c compressor puts a lot of strain on the engine because the compressor is similar to being a small engine itself. When the a/c is switched on, the engine control unit should trigger components such as the idle speed/air control motor, to increase the idle slightly to compensate for the extra drag of the compressor. If that does not happen, then the additional drag can cause a low,shaky idle and even cause the engine to stall. It’s probably a good idea to have a professional mechanic come to your location and complete a vehicle is vibrating inspection, so they can isolate the source of this problem and recommend the right repairs.
My truck shakes at traffic lights
ANSWER : Hi. The symptoms you describe could be a dirty or malfunctioning idle air control valve. Especially when hot, when the engine gets a leaner mixture of air and fuel, the idle air control will have a greater effect on idle and low speed running. In general, it will not set a Check Engine code either. I would recommend having a rough idling diagnostic completed by a mobile professional mechanic, such as one from YourMechanic, to inspect the problem and replace the idle air control valve if needed.
I changed fuel pump and truck ran great for 3 days. Now after 3 days truck dies. It will start runs few min then dies like before
ANSWER : Check the bottom of the fuel tank for sediment. Age and mileage could have accumulated a lot of it at the bottom of the tank. If you did not, check and change the fuel filter. Rule of thumb – replace the fuel filter any time you replace a fuel pump. Also, check the wiring for any chaffing on the fuel pump when you remove it. While your problem is kind of unique, I have seen many GM truck fuel tank baffle loosen over time, occasionally rubbing against the fuel pump can intermittently short it out and/or block the fuel pump pick up. To have this diagnosed, consider having a certified expert from YourMechanic inspect the stalling issue to have this corrected.
My truck has a violent shake, rapid onset, massive white smoke, increases shaking with turbo charger pressure increase, and has an error code of p0303.
ANSWER : Hi there. If you are having a misfire on cylinder number 3 and the injectors are new with the fuel lines cleaned out, then the exhaust valve is burned on cylinder number 3 and needs replaced. This is why there is white smoke in the pipe. White smoke on a diesel engine is unburnt fuel from the misfire. If you need further assistance with the vibration and a misfire on your diesel engine, then seek out a professional, such as one from Your Mechanic, to help you.
I changed the fuel pump and truck ran great for 3 days. Now after 3 days, the truck dies. It will start running for a few minutes, then dies like before.
ANSWER : Hi there, thanks for writing in. I’d be happy to help. It sounds like you should disconnect the connector to the fuel pump and inspect it for any signs of getting hot. The female connections may be too loose on the fuel pump and lose contact after running and getting hot. If there are indeed any signs of problems, then I’d suggest replacing connector and adding dielectric lube to pins before installation. This should solve the problem, but if you continue to experience issues, feel free to reach out to us for help again.
Truck running rough. Shaking while idling and seems to shake more when accelerating.
ANSWER : A faulty oxygen sensor can certainly cause an engine to run rough and cause a bit of shaking due to the imbalance in the air/fuel load. As you may know the [oxygen sensors]((https://www.yourmechanic.com/services/oxygen-sensor-replacement) which are part of your emissions system read exhaust gases to determine whether or not the appropriate amount of oxygen is present in the exhaust. Based upon this reading, this information is relayed to the car’s ECU which then makes a determination as to whether or not to add more or less fuel to the engine. When too much or too little oxygen is present, this will cause check engine light to come on. Too much oxygen may be present in the exhaust gas due to things like an exhaust leak, a vacuum leak, a faulty mass air flow sensor (causing a lean fuel condition) or faulty fuel injectors. Too little oxygen may be present in the exhaust gas may be caused by things like a clogged air filter, a failing mass air flow sensor (causing too much fuel to be introduced to the motor), bad fuel injectors or a clogged catalytic converter. When the O2 sensor is not working properly, this will cause false readings to be relayed to the computer causing inaccurate adjustments to be made to the intake and fuel system in your engine. You may also notice a very strong smell of fuel and poor fuel mileage. I would suggest having an expert from Your Mechanic come to your location to diagnose your truck’s running condition.
The truck intermittently, has a very rough idle, and runs rough,usually after warming up.
ANSWER : Hello. This can be caused by a number of different things. If this occurred right after you had gotten fuel then I would start by testing the fuel pressure. I would do this when the vehicle starts running poorly. It is possible that the bad fuel contaminated the fuel pump and it is not putting out the right pressure. If the fuel pressure is fine then I would check the other sensors readings with a scan tool. One other common thing that I have seen on this engine is a leaking intake manifold gasket. It starts leaking on the bottom side and that leak causes the MAF and MAP to not read correctly which causes it to run like this. If you would like to have this rough running condition looked at, consider having a YourMechanic certified techniciancan come to your home or office to diagnose why it is running rough.
Throttle body changed 3 days ago. Idle relearn performed and still high idle and revving while in park.
ANSWER : Hi there. Check the engine for a vacuum leak. Check all vacuum lines, hoses, and the intake for any leaks. Also check the brake booster for any leaks. A vacuum leak will increase the engine’s idle speed while the engine is not loaded. If you need further assistance with your engine revving in neutral and park, then seek out a professional, such as one from Your Mechanic, to help you.
