Why would a car run smooth some days and rough at other times?

1. Why does my car run rough sometimes?
2. What causes intermittent rough idle?
3. Why does my car vibrate intermittently?
4. Why does my car start rough in the morning?
5. Can a bad o2 sensor cause shaking?
6. Can a bad air filter cause rough idle?
7. Can dirty fuel injectors cause rough idle?
8. Can clogged catalytic converter cause rough idle?
9. Can transmission cause car to shake?
10. Can a bad alignment cause shaking?
11. Why is my car shaking and engine light on?
12. What are the symptoms of low fuel pressure?

Why does my car run rough sometimes?

Causes of a rough idle. 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 causes intermittent rough idle?

A rough idling engine can be caused by spark plugs or spark plug wires. Spark plugs use the electrical current received from ignition coils to ignite the air/fuel mixture within the combustion chamber. A plug that is damaged or installed incorrectly can result in fuel being burned at an inconsistent rate.

Why does my car vibrate intermittently?

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. ... Wheel alignment should also be performed at proper intervals.

Why does my car start rough in the morning?

There are many causes of hard starting but illustrative ones are a faulty engine coolant temperature switch (sensor), malfunctioning idle air control (IAC) valve, vacuum and EGR leaks, inadequate fuel delivery or pressure (clogged fuel filter, injectors), and contaminated or old gasoline.

Can a bad o2 sensor cause shaking?

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. ... When too much or too little oxygen is present, this will cause check engine light to come on.

Can a bad air filter cause rough idle?

Poor Engine Performance

Engine misfires, rough idling and hard starts can all be traced to a clogged engine air filter. The dirty air filter restricts the air supply to the engine causing unburned fuel to form a soot residue that accumulates on the spark plug.

Can dirty fuel injectors cause rough idle?

Your engine fuel injectors can collect grime, dirt, and soot leading to an air-fuel mixture imbalance for your car. When this happens, you may notice poor performance, rough idling, and inconsistent gas mileage over time.

Can clogged catalytic converter cause rough idle?

A clogged converter can cause rough idle, engine hesitation upon acceleration, weakened power, hard-starting and, in some cases, a no-start condition. ... This symptom can be diagnosed by using a vacuum gauge on the intake manifold, or an exhaust back-pressure pressure gauge before and after the converter.

Can transmission cause car to shake?

Car Shakes When the Gears Shift (for both manual and automatic transmissions) Normally functioning transmissions keep your ride smooth during gear shifts. Automatic transmissions that shift hard, jerk or shake during a shift change may mean your transmission fluid needs changed or fluid level is low.

Can a bad alignment cause shaking?

“Why is my car shaking?” —This common vehicle issue is often assumed to be the telltale sign of a tire alignment problem. It is true that alignment troubles cause road unsteadiness, shaking, vibrations, and uneven tire wear; however, warped brake rotors and tire imbalance can have similar symptoms.

Why is my car shaking and engine light on?

Usually, when the check engine light is on and the car is shaking, that means you're dealing with an engine misfire. Basically, the check engine light comes on whenever there's an issue that could increase vehicle tailpipe emissions.

What are the symptoms of low fuel pressure?

Decreased Fuel Pressure

Low fuel pressure can lead to engine misfires, low acceleration, rough idles, and engine stalls. If your check engine light is on and your car has been stalling out, you may have a fuel pump failure.