New issue with my 2003 STR. The engine runs very rough at idle while cold, I'm getting lean codes on both banks and restricted performance, and there is a weird whining or whistling sound which appears to come from the front of the engine near the supercharger snout. The sound dissappears briefly if you blip the the throttle, but then quickly returns. If I roll into it the sound remains constant except for the split second as the throttle is first opening. The frequency, volume, and tone of the sound don't seem to be RPM dependent.

Recently had the charger, coolers, and intakes off to replace a bad injector and some other general housekeeping (valley pipe, cleaned intercoolers, etc.) and the issue started not long after this. I don't know if these issues are related, but they all appeared simultaneously. Also sometimes under moderate to heavy aacceleration the engine will stutter or stall briefly. Please help.

 

Sounds like an air leak. The recent work is #1 suspect.

(Maybe a gasket slipped or some such.)

You might try spraying (propane or even a mist of water) at or at least close to the suspect area to see if the STFTs change as you do that.

 

Definitely leaking. Sprayed carb cleaner and got a response from the front of the engine just below the supercharger.

 

spray brake clean and watch your trims

outlet duct to intercooler side seals. the big rubber hose. brake booster vac fitting if it's really bad