Idle low when warm?

A few months ago, we had an issue with the timing chain. We replaced timing chain and guides, coil packs, coil pack housing, injectors, plug and boots. It ran great for about a month. Now my idles at 500 RPMs when warm. When I stop it seems to sound like it’s going to stall out, but it hasn’t yet, it’s using more gas than normal, and it has lack of power when speeding up on freeway, and There’s a loud rattling noise (only when at operating temperature). My son scanned it and it’s not throwing a code, no check engine light. He checked my oil pressure which is fine when cold but once at operating temperature it drops very low. I’m not sure what to do next.