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Q: Hi - Knocking noise

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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.

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.

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