I just put a 97 2.2 from a legacy in my 98 outback. I have a knock sensor code that wasn't there when the motor was in the legacy. Any thoughts.

 

Also when I am driving and give it gas I hear a whistle sound now.

 

Thanks

Knock sensor codes are usually because of corrosion on the sensor or the housing of the sensor is split and the element inside has corroded.

Easy to check, and only about $15 on eBay for a replacement.

 

Is the whistle from the front or back? If you have the big box intake make sure the halves are fitted together properly.

Alot of these have a whistle sound from the muffler. I'm not sure if anyone really knows what causes it. My 96 does it, my girlfriends 95 does it. I've heard countless others make the same sound. My old 95 wagon had three different pitches depending on engine speed and throttle opening.

 

Also when I am driving and give it gas I hear a whistle sound now.

 

a leak,

exhaust or intake.

have someone accelerate the engine while you listen.