Engine noise -off beat scraping - 2004

I'm shopping for a truck right now and came across a first gen tundra that fit my needs for a work truck. I get there and the body is as expected, the frame is in good shape, etc. It starts good, no smoke, runs good for 200k miles.

I take it for a test drive and everything's fine, but here's the catch, after it gets warm it has an off rhythm scrape in the engine at idle. The guy told me it's common, but this isn't something I know of as common. It's not a lifter tick, it's something that's off rhythm but consistent.

Anyone familiar with these engine noises and potential causes?

There are some additional reasons I'm interested in this truck, so if possible I'd like to get more info on potential engine noises/problems prior to paying for an inspection.

 

Any way you can get a video of the sound?

 

Not now, I should have taken one while I was there.

 

Scraping is a weird word when describing engine sounds. Maybe belt idler pulley ?? Just guessing

 

It could be one of the accessories. Power steering, air-conditioning, alternator or any of the pulleys. But you say it’s inconsistent, makes me think that it’s something cycling, and that’s when you hear it. Like your air conditioning coming on and off because it’s low. Or an alternator making a noise when it’s under load.