whenever i accelerate my avalon, especially in lower gears, there is a noise that sounds almost like a deisel engine when it accelerates. It started to happen after i would go up steep hills, but now it is more frequent. however, when going at an even speed i can't hear the noise. what are possible causes? I'm afraid it will be really expensive.
What year and how often was your oil changed. Might be just a bad muffler.
Take it in for a checkup. May need a new O2 sensor or something related.
Sounds like you are hearing "pinging." Try a higher octane fuel and see if it goes away. If it does, you can continue with that higher priced stuff or determine the cause of your detonation which could be incorrect timing, too lean a mixture or other causes. Good luck. jor
>i have a 2000 w/130,000 miles. i change the oil every 3,000 miles regularly.
If you find it happens more frequently when the engine is cold and changing to higher octane gas doesn't cure your noise, do a google on something called "piston slap". I had a Lexus that started with symptoms of piston slap at 35K miles, and yes, all maintenance had been performed on time.
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