I have a 2000 Lexus ES300 w/ 194k miles and I just replaced the 2 air intake hoses that connect straight into the throttle body since they were cracking pretty bad. While I had the hoses out, I cleaned the throttle body entrance, spray seafoam through the idle air control valve with the bottom hose of the valve disconnected so the seafoam can flush the carbon out, and suck the seafoam through the brake booster vacuum line into the throttle body. After that everything is fine, the engine feels more responsive after I cleaned the throttle body. However, I noticed the engine make noises similar to knocking/tapping whenever it is idling. It takes a few minutes after starting the engine for the noise to come on and some seconds when the car is stopped on the road for it to come on. I don't hear it when I give it some gas or driving 80mph on the highway. Is this because I cleaned the throttle bottle and knocked some debris loose or is it something more serious? Other than the noise, which I barely hear while inside the car, I don't feel any performance loss.

Video link: The noise is around 3:33 mark

 

Try pulling vacuum lines off the EGR modulator back part of the engine (remove engine cover). Looks like this

 

I'll do it maybe tomorrow since it's dark out right now, but what am I supposed to look for/do once I pull the lines out?

 

See if the noise stops or changes.

 

Found the culprit after taking the engine cover off. One of the hoses under it broke off. I put electrical tape over it and the noise went away. It was a hose connected to the green tab near the brake master cylinder. Pretty sure I accidentally pulled on it whenever I replaced the intake hoses. It was very brittle to begin with from 23 years of engine heat.



Also, I have OCD so I cleaned the area under the engine cover and accidentally broke one of the small hoses at the connect point, the thing that extrude from the connect point for the hose to fit over stuck inside the hose, so I just superglue it on there and put electrical tape on it to hold it. I'll try to find that piece whenever they have my car at the junkyard. I should not be working on my car lmao

Thanks for the help!