I'm curious to see if anyone knows of a solution to this, my '02 outback (2.5, man) likes to emit a pretty quite "pop", almost like a backfire, most often when upshifting from 1>2 or 2>3.

 

Did a little reading, maybe just some unburned fuel being dragged into the exhaust manifold?

 

It's nothing I can't live with, doesn't always happen, just a bit curious if others have any suggestions, thanks.

Nick, I have the same phenomenia on my '02 Forester L 5sp. I have complained to the dealer and opened a "case" with

Subaru about it. I now have 45k on the car and it still happens. They say they have no record of anyone else having this issue.

The reason I make a big thing about it, is I've had 4 oxygen sensors replaced. The Last one lit the Check engine light right at the time I shifted and had one of these 'pops'.

Yes I can and have lived with it. For me if it did NOT take out the O2 sensor, I probably would not have been so upset. But my point is, If it continues and out of warrenty takes out the sensor at over $100 a "pop", this is an expensive engineering issue, at least for me. which is being pushed under the carpet.

My 2.2 manual legacy will do a little burble imitation of a backfire when I upshift. That is, I usually blip the throttle on the upshift, I'm assuming you both do the same, or do you let the clutch do the work??? Not sure why soobs do this, but it doesn't bother me. I've heard of some rally and drift cars that use a "backfire system", making the car backfire on close throttle, but I don't know what it's for. I guess it just sounds cool :-P

 

ScoobySchmitty:banana:

I have seen bad EGRs cause backfires.

They got rid of the EGR in the evolution from the 2.5L DOHC Phase I engine to the 2.5L SOHC Phase II engine.

 

Sorry, I can't offer anything on this one. Would a manifold leak do anything like this?

 

Commuter