Topic: loss of power on top end

[foresterfan]

2004 forester xt- 222,000 km
So recently my car developed this habit of power loss at (and only after) 4200rpm... had a front O2 sensor code- so I changed that, then a misfire code so I swapped out the plugs and coils, cleaned the maf sensor just for also had codes cleared by a shop (no personal code reader). Has anyone had this experience? Car runs and idles fine, and as long as I do not mat it off the light there is nothing out of the ordinary, fuel consumption is normal. Totally stock set up.

Thanks

[fleetwood79]

Catalyst came loose inside the exhaust? The pressure of the exhaust will push the bits back and block the exhaust flow. If the cat is rattling, the pipe has a difference in temp just before or after the cat or less exhaust flow with your hand on the tail pipe while somebody reves the engine will be signs.


Misfires and weird o2 sensor faults could result.

[foresterfan]

You sir are correct.

Pipe finally arrived last week and I got it in with little hassle and all is good.

[mojikita]

Catalyst came loose inside the exhaust?

Nice diagnosis! Respect.