Q: Hi - Knocking noise

asked by on September 29, 2016

Hi I have just pour fuel injector cleaner in my fuel tank. As driven about 290 km my car has start knocking in 40-50 kmph. It goes away as I accelerate more or drive between 25-30 kmph. What should I do now to make my car smoother again. My car talking a little long self when its hot, so I pour injector cleaner. Now two problems are present. 1. Long self when hot. 2. Knocking sound

Car is 1000 cc 2nd generation VITZ By TOYOTA

My car has 153000 miles.
My car has an automatic transmission.

Fuel Pump Replacement $145.32 - $1299.70 Get a Quote
Car is making a noise Inspection $94.99 - $114.99 Get a Quote

Hello. If there is a knocking noise then it may have some bad fuel or it may be another failure like an internal engine problem or a bad sensor. I usually start the diagnostic process by scanning the computer for codes, checking to see if there are any sensors that are reading incorrectly.

If those are all fine then I check the fuel pressure to make sure that the fuel pump is fine and then do a compression test to see if there are any internal engine issues.

If you want to have this repaired, consider YourMechanic, as certified mechanic can come to your home or office to diagnose the sound firsthand and help you make an accurate repair.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

How do I correctly wear a seat belt?
Seat belts are extremely important safety features that can reduce injuries and prevent death in the event of an accident. However, wearing a seat belt properly is very important, or else you may not get the full benefit of the...
How do I change the ringtone volume?
The volume of the ringtone on an incoming phone call can be changed very easily. To do so, follow these steps: Press the Setup button. Press phone, phone sound settings, ring tone choose ring tone volume. Then adjust volume level....
Fixed car after Service Engine Soon light came on. It's still not working right
I can understand how frustrating it can be to replace parts on your car only to have it continue to experience problems. There can be several reasons why your Pontiac has its’ Service Engine Soon Light illuminated. If there is...
Noisy whirring sound when I step on the gas pedal.
Hello, thanks for writing in to YourMechanic. It sounds like you may have a problem with the serpentine belt driven accessory like a tensioner pulley or the alternator bearing is bad. If you'd like to have the noise from the...
Car is making a noise while idling. It sounds as though a motor bike is nearby. What might it be and is it safe? 2000 BMW 528
Hello - the sound you hear is most likely the electric cooling fans coming on while the vehicle is stopped. The lack of airflow across the radiator while stopped or moving slowly causes engine temperature to rise, triggering the cooling...
Message come up Reduce engine power
A reduced power light usually indicates a fairly serious problem with the throttle system. When this light illuminates the vehicle will often go into a “safe mode”, which will severely limit the speed of the car and in some cases...
Vehicle stalls while turning left.
Hello, and thank you for writing in. The first thing you should do, considering the power steering pump is driven by the drive belt, is make sure the belt tensioner and the drive belt is tight, clean, and dry. If...
engine overheating.
Hi there. When an engine is overheating your would need to check the coolant to see if its low or not the correct temperature rating. If the coolant is good and rated to the maximum temperature, then the radiator could...

Related articles

A Buyer’s Guide to the 2012 Toyota Highlander Hybrid
You’re You’re likely already familiar with the much-celebrated Toyota Highlander, but did you know that Toyota has actually offered a hybrid version of everyone’s favorite crossover SUV since 2006? The 2012 Toyota Highlander Hybrid is one of the most exciting...
2012 Toyota Camry vs. 2012 Chevrolet Malibu: Which One Should I Buy?
Mid-size sedans are the perfect family vehicle; offering just enough space for you and a few kids, but not so much that a small family will feel lost in them. This class of vehicles is slightly larger than a compact...
How Long Does a Top Dead Center (TDC) Sensor Last?
The The top dead center (TDC) sensor is the point from which the firing order is determined and the ignition system measurements are taken. The measurements are normally defined as before top dead center and after top dead center. The...