Looking for troubleshooting assistance with my 04 Subaru Outback 4cyl MT. It has a very noisy intake and anemic performance under 3k RPM.

I mistook the noisy intake for an exhaust leak so I replaced the exhaust manifold gasket but the problem persists. I’m new to car maintenance, with a background in computer hardware support. Any help would be appreciated.

I’m not sure what’s causing this. Could this a valve/vacuum/timing issue?

 

Edited August 8, 20196 yr by clinternet

when was the timing belt system last serviced?

Is the cel on and what codes are stored? (parts stores can scan for trouble codes - or a phone app and an ELM327BT adapter can be helpful)

holding some small tubing to your ear and moving the other end around the intake tubing and other spots - maybe you'll hear a loud sound?

 

Check the EGR tube. 

GD

Engine has 167k miles. Timing belt and head gasket replaced within 2k miles by seller. 

No CEL currently lit. A code reader is a great idea tho. I just ordered a BlueDriver scan tool that will be here Friday. I will report back with what I find.

EGR tube sounds like a good place to start. Maybe I should soak it in carb cleaner? I was considering giving her the ol’ Sea Foam treatment.

GD called it. It was the EGR tube!

Pipe was completely chopped. I repeated the previous hillbilly fix with 2 hose clamps and a 2” piece of hose for now. New OEM EGR tube inbound at Peninsula Subaru in a few days. 

Thank you both for your insight to a noob question! I owe you a beer the next time I’m in Milwaukie. 

Edited August 10, 20196 yr by clinternet