Hey, so I got this 2021 wrx that started making a rattle noise only when I give it some light throttle. To be more exact it happens between 1k5 and 3krpm and only when the boost gauge reads between the -10psi and -5psi.
I ruled out a few things already and I'm sorta looking for any ideas on where to look now.
- Changed and checked the oil, there is no sparkles, no nothing. Oil level is perfect.
- It drives fine and builds up boost, rattles gets mostly drowned out by the wind.
- Took out the belt to rule out any of the pulleys or accessories.
- I walnut blasted the intake recently.
- spark plugs are pretty new (10k miles) and no oil on them.
- Checked all the exhaust and header heat shields, they were all tight.
The only clue I got so far was that the top turbo shield seems to almost if not touch what I think is the actuator rod.
I have no cel, no misfire, car drives really good. It doesn't seem like rod knock to me or piston slap but I could be wrong? I was also thinking about the timing tensioners but the noise is more at the back of the engine.