Greetings, checked the search but couldn’t find anything related to what is going on with my Cobalt.
So, I had this weird rotational rattle, sounded almost like a playing card in a bike spoke. It was directly related to RPMS. It rises and falls with revving, starts at around 1000rpm and can hear it up to around 2-2500. Thought it might be timing chain tensioner as I’ve seen thousands of threads about it. Replaced it last night (with the newest revision version) and cranked it after. Sound appeared to have gone away, but idled at 1200 rpm’s and wouldn’t budge.

Cranked it this morning, let it warm up, and what do you know, the sound is still there. Probably just masked last night by my cold air intake sucking every ounce of matter within a 10 foot bubble. Sounded like a jet about to take off.

Pulled in the driveway and heard the normal LNF DI noises; then this really odd noise. I’ll post videos of it. Need help figuring it out. Only thing I can assume is it’s the HPFP?

Also, the car is throwing a P0326 for boost sensor, will maybe make 5lbs of boost and then falls. Feels like it wants to build pressure but can’t hold it?

https://youtube.com/shorts/LfxDVe05XAU?feature=share