1 Lucky Texan

there shouldn't be any differential pad wear in theory. My limited experience is that the inner pads wear slightly faster than the outer pads. The caliper on that wheel may have been sticking slightly and unable to slide outwards easily, leading to more wear on the outer pad.

you may have 2-3 problems, not impossible with an older car. the brake issue needs to be addressed. The caliper should be able to slide on the pins, rust should not interfere with pad or caliper movement, etc. It's also possible to receive aftermarket parts that are built wrong, or are intended for a different model. "warped' rotors are often due to a panic stop putting a deposit of pad material in one position. If the pads/calipers on one side have been overheating the rotor, a 'bedding in' procedure might help, if it doesn't, you may need a new rotor. the car may have worn inner tie rods or other steering parts/bushings. try swapping rear tires for the front. Good time to inspect, calipers, pads, lug nuts and studs, and wire-brush any flaky rust from rotor surfaces. check the alignment. while a fairly simple system, brakes have a lot of important details and can be a challenge to get into top condition on older or neglected cars. bearings; Subaru bearings can fail with several different symptoms. with the corner or end of the car in the air, rotate the wheel while feeling the spring for roughness - or get a mechanic's stethoscope and listen to the hubs. Also, a bad bearing will sometimes allow the wheel to be lifted/rocked up-and-down in the 12 to 6 o'clock direction. any movement is bad - compare side to side.

not common but, that caliper may have a stuck piston or bad hose - w'ever the actual reason, the caliper is not free to slide and center itself. As said, most often it is rusted or bent caliper pins or bad rubber pieces on them.

I've only read about this stuff, so, not speaking from experience. The round access cover seems very stable, From reading across a coupla forums for years and looking at pics of leaking plastic a/o separators and seeping rear mains, I THINK I have only once read of someone with a leak from that cover (wrist pin access?) I probably wouldn't disturb it if dry.

any chance of rust holes in the filler tube?

some folks seem to report good results from running marvel Mystery oil - you might research it. (maybe it frees-up lifters that are gummy?)

hmmmm....sometimes weak TB tensioners will mimic rod knock.

have you tried locking/unlocking (actually, setting/disabling the sec. system) with the fob a coupla times?

If the ECU responds to that knock sensor by drastically pulling the timing, it will make the car very sluggish and likely be detrimental to mileage. On some engines, care must be taken to route the cable/connector in the same ways as the original knock sensor. There is a lump in the casting that can lead to cracking a knock sensor if it isn't oriented correctly. maybe it took 500 miles to break?

easy to check the belt's timing, pull the covers, set the marks - find the tooth count for your engine for a triple check. If you reset the ECU (with a scanner or with a battery disconnect) does the car run better at first? check for a stuck caliper, maybe a brake is dragging?

when was the Avalon introduced? yeah, a long time

a Toyota Avalon would be the best car to back away from an eruption. because, backwards, it spells; no lavA HAHAHAHAHAHAHA *cough* HAHAHAHAHAHAHA!!!!!

I'm not sure about a 99 EJ22, but the 'cheapest' kit for that 2.5 interference-engine is the one least likely to fail before the next belt service.

one idea, contact user 'traildogck' over at subaruoutback.org - he even does mobile repairs and casts his own line of bushings!

look for 'chaos' behind the timing covers try jump-start from another vehicle? try turning the crank pulley by hand with a big wrench

does it crank but not start - or no cranking?

oem got shorter in 06/07 - maybe pull from a wreck and swap? or check the usual suspects; cusco, grimmspeed, kartboy, whiteline etc. ?

It's why you constantly read recommendations to change the rollers at the belt service.

belts are tough toothed idler? - not so much.

my guess would be mercury switches probably abandoned in the early 2000s or before, so, right on the cusp lol!

best answer is, doesn't 'seem' to be as common in older cars. but 2009 ? even the 2.5 is not so bad I think as older generations. keep in mind, there are fewer of them in the population so data is tricky to discern. They certainly CAN have HG issues.

I think you can plug the 2 test connectors together under the dash and the relays and fans will cycle.

^^^^ most likely ECU doesn't know the engine is cold, so it doesn't 'choke' it with xtra fuel sent thru the injectors. on your car, there may be 2 sensors. single wire I think is the gauge, 2 wire is for the ECU - maybe near each other on the coolant crossover tube?

learned something new.

if the hatch plunger switch were on the hatch, I'd suggest abraded wiring in the body-hatch boot.... but I think the switch is in the body?