I’ve been having an issue since January when I’m about to stop for a red light or stop sign the RPMs drops to 500 and the car vibrates with a weird noise coming out of the passenger side wheel fender area and then goes back up to 700 where it should be and it stops vibrating. It then drops to 500 and goes back up to 700 while idling this doesn’t happen every single time but majority of the time. I’ve replaced the timing belt, water pump, tensioner pulley, spark plugs, motor mounts, engine air filter, transmission fluid drain & fill with the filter, cleaned the throttle body, MAF & MAP sensor with the relearn afterwards all in the last 9 months with no luck. I’ve taken it to numerous different mechanics around Southern California and they can’t figure out what the issue might be. Could it possibly be the brake master cylinder or the water pump? I would appreciate the help/advice thank you!



Below is the link to the video I recorded of the weird noise it makes while at idle. The noise grows a bit when I start to accelerate and then goes away once I go past about 10 mph.

https://youtube.com/shorts/Kv9q2Mvvtso?si=D4wM8npWyDrOQTwP

 

your battery is going bad making the ECU forget the idle learn. Get a new battery and do the relearn and your issue will be fixed.