how many sensors and much to replace o2 sensor

I've replaced the cat. conv. twice in the past year. Now, the car is not running, codes throwing for cat. conv, o2 sens, knock sens, lean running... By the time I figure out whats ruining the cat. converts I'll have spent WAY more than the value of that car. I'm a single mom, college student and drive ALOT! Time to trade in?

I overfilled my oil when doing my oil change. Drove maybe 50 miles on the highway and when I stopped I could feel my engine shaking. I promptly returned home and changed my oil (When I drained the oil it was jet black after maybe 100 miles) and filled it to the proper level. I figured that I may have fouled a spark plug so I changed them with no luck on stopping the shaking. I've been checking to see if I am losing oil and I am not, there is no sound to accompany the shake nor have I had any smoke coming from anywhere. As soon as I accelerate past idle the shaking stops. Seems that the shaking gets worse as the car heats up, its not near as bad when I first start it.

My brakes are very very weak. When i got the car the brake pads were pretty slim so i changed them. One back rotor is pretty torn up but still workable, but the problem is there was no difference in the strength of my brakes after bleeding, changing pads, and there are no leaks to be found. Any ideas?

where can i get rocking pinion boots for forester 02??

I lost the timing belt at 104,000 Blew the engine. This would be for a full swap to a used motor of equivalent miles.

It will be used for everyday travel of at least an hour distance.

has a misfire code on two cyl.s now. It had a code for cat. I replaced it.[Eastern] It seemed alright but fuel economy was not good and then noticed cat was getting cherry red.Understand why. Changed spark plugs which looked fine. Compression test good. Changed O2 sensor & sp wires both Denso. Had ECU flashed. Since the problem occurs after driving &restarting thinking coil

Check light code is P1443. I can see no leaks. Only happens in very cold weather. Smell seems to be coming from heating vents. Do I have to pay $90 for a full diagnostics?

No drips on garage floor

sticks in cold weather

My 2002 Forester has recently had a lot of word done, including new tires. It seems like after the tires were put on a few days later I noticed that the interior noise was much louder. Seems like it is coming from the rear. I've had these Pirelli tires before, no issues like this. The noise is constant, getting louder with increased speeds, same in neutral is in drive. Ideas?

My air conditioner works well for a while, blowing very cold air. Then, suddenly the compressor seems to shut off & only warm air is emitted. This seems to happen especially on hot days (sometimes on cooler days too) and especially if I am in stop and go traffic or waiting at a light. If I accelerate to a higher speed, like when on the interstate, the compressor seems to kick back in. I can do this 5 or 6 times. Eventually, even that fails. Then I have to turn off the system and let it rest. About 10 minutes later I can restart the air conditioner, and it cools perfectly. I recently had the freon refilled and the system checked for leaks by mechanic but no leaks were found. Then it happened again and that mechanic had it for an entire day but said they could find nothing wrong with it. So I finally gave up and took it to Subaru - they said it's both head gaskets leaking and that I should have then replaced plus they recommended replacing the timing belt and the water pump at the same time at a cost of $2800. I can't find anything about leaking head gaskets causing a/c troubles and I've read on some other sites that other Forester owners have the exact same trouble even after replacing the head gaskets so I am not sure if I trust that the dealer is telling me the truth about this. Any help would be greatly appreciated.

When I run the A/C, after a short time, warm air blows out of the vents. I had the freon charged / refilled and the system checked for leaks by mechanic but no leaks were found. It had been in 90's when it first started but when I picked it up from mechanic it was cooler, only 83 degrees outside. I did not notice it happening then but a day later, it still doing the same thing again. Any suggestions greatly appreciated!