Wierd Rattling Noise From Engine When Accelerating

[topgun129]

Hi,

I have a 99 Lexus ES300. Lately, I've been noticing when accelerating (*especially* in an incline/uphill) there is a weird rattling noise coming from the engine (kinda sounds like a diesel engine). I can't feel any vibration of any sort but the rattling concerns me when I'm on the accelerator. Is this a common issue?

If I take my foot off the accelerator and let the car coast the noise goes away.

Has anybody here experienced something like this before?

Thanks!

[pj8708]

Hi,

I have a 99 Lexus ES300. Lately, I've been noticing when accelerating (*especially* in an incline/uphill) there is a weird rattling noise coming from the engine (kinda sounds like a diesel engine). I can't feel any vibration of any sort but the rattling concerns me when I'm on the accelerator. Is this a common issue?

If I take my foot off the accelerator and let the car coast the noise goes away.

Has anybody here experienced something like this before?

Thanks!

I'm not an expert, but it sounds like your basic engine knock/pinging usualy caused by useing a gasoline with to low an octane rating. It might also be the engine timeing set incorrectly.

[gbhrps]

I agree with Paul A. You may well have a condition called preignition from low octain fuel use, improper timing, or carboned up pistons and valves. Continuing to use the car when its pinging will eventually burn holes into the tops of the pistons or worse. Read:.....very expensive to fix at that point. You need to start using premium fuel, and if that doesn't correct the problem, get the engine checked out. Good Luck!

[rushlvr]

It is also sometimes a warning that a knock sensor may be going bad.

[Corditebox]

I had this same issue and for me it was the start of an issue with the knock sensors. When the car was driven in colder climates the problem went away, but eventually it morphed into the dreaded limp mode. One day I lost overdrive and got the chk engine, trac off lights which was the cars way of letting me know that it was an issue that had to be dealt with immediately. This all took place a year after the tingling first started.