I purchased a 1999 Legacy Brighton 2.2L manual transmission wagon in Dec 2011 with 189k miles for my college son. I purchased it from the original owner who gave us complete repair records including original purchase receipt - the clutch was replaced at 179k... timing belt and head gaskets, valve cover and O2 sensors at 187k... all expected maintenace done on time... only issue was a leaking power steering pump which occurred when timing belt was replaced - the power sterring pump has now been replaced twice but still leaks?? That is a separate issue.
At around 200k the engine started leaking a bit of oil from the rear engine seal. About two weeks ago he was unable to make it up the hill to Tahoe - high RPM but no power. He smelled buring oil - which I believe is the rear oil seal leak onto the exhaust manifold/muffler. I checked all engine codes with scan tools and all is good. Reading the boards I thought it might be the mass air flow sensor and the scan tool did read it eratic but when I went to Autozone the MAF sensor they had for a 1999 did not exist on my engine instead the 2000 model year 2.2L air flow sensor did. This is despite the fact the engine serial number matches the VIN etc... is this a phase two or phase one 2.2L engine??
Anyhow replaced the air flow sensor, plus the air filter, the fuel filter, the spark plugs and spark plug wires.
And still no power...
Clutch in 5th gear with brake on stall engine and replaced at 179k I believe it is good... All codes read clean... the engine is not burning any oil nor blowing any blue smoke... no noise from the clutch and all trans gears shift smoothly...
Just no power - difficult to get power over 55-60 MPH and on a steep hill just no torgue at all... everything else runs great..