1 Lucky Texan

^^^ superb and succinct explanation. Was any other work done? maybe check the parts list for coolant system parts. But, impossible to definitively lay blame on the shop.

^^^ yep,I was gonna say fuel, and maybe ATF - but, it depends on the actual polymer used.

changing the 2-3 largest hoses preemptively makes sense to me as you might severely overheat before getting off the road. Ths smaller ones likely give you enough time before you go dry so, unless they are easy to get to and inexpensive, might just wait until they leak. Of course your personal situation makes a lot of difference on this type decision. If you rely on a 15-20+ year old car for critical transportation or long distances driving alone,etc. , you would want to address ANY issue that could strand you. maybe even carrying a starter, alt. and fuel pump even......plus tools lol! and repair tape as mentioned, JB-Weld, and other similar repair gear would be good to have with you.

if you can't match it, as an emergency measure, see if you can make a bigger 'loop' with straight generic hose. Smallest 3/4 circle that doesn't kink. Tie/support it out of the way with some cord or zipties strung together.....? like this ____(

well, maybe the FSM has some guidelines for testing sensor signals - could be that the actual sensors are OK, but a wire is broken or a pin is pushed back in a connector. Testing resistances from the ECU's connector and comparing values with the FSM could locate the problem. If the car was OBDII, live data would be very helpful. Maybe someone else knows how to get live data from a '93. If the car also struggles to rev past 5K at idle, maybe try a squirt of raw propane, or starter fluid. maybe the fuel pump is weak????

coupla wild ideas; when you were monitoring the sensors, how did the engine temp sensor look? ? also, is this the first year of DBW? could this be electronic throttle problem?

how does it run immediately after a battery disconnect reset? If badly, look for something 'physical' like a clogged exhaust or 'dropped' valve. If better, could be a bad sensor or sensor wiring....

knock sensor needs attention. I wouldn't rule out partially clogged exhaust. Vacuum gauge might show that.

is the trans pan dented?

coupla things; 1. You could investigate Blackstone labs and test your used oil. 2. You might enjoy reading at www.bobistehoilguy.com

Has your car ever had a timing belt system service? not clear on your mileage.......

GD may have the best view on this subject, but i DO believe CAFE rules have pushed car makers to slide the viscosity scale downward in the US market. It may be worse on recent vehicles (say, 2014, 15+ ?) And it seems in other markets, the engine oil viscosities are higher for the same engines. My wife just bought a Honda CR-V and on the main forum for that car, they also show the same car in Europe with a heavier weight oil recommended. Also, your location is distinctly different from mine. I am comfortable using heavier weight oils (certainly at the 'top' number) due to ambient temps here. It is said the most wear is starting a 'cold' engine. At that moment you have zero oil pressure. The thought that I park my car for hours at work, let it sit in direct sunlight in August, then go and start it when it could be 120*F or w'ever underhood - makes me wonder if 20 or even 30 weight oil has left ANY protecting film behind in the journals/bearings. And the question is even MORE important for an engine that could have 150K miles of wear. Some Subaru engines also have had a too-small oil pump from the factory, others may recall if your 03 for instance would benefit from a different pump (anyone?) Anyway, it's a very good question, not new, but worrisome, and worth trying to get a consensus from people.

^^^^ yep I THINK I have seen step-by-step pics or maybe a video on swapping the u-joints.

sure seems like a pinhole in the condenser. Not 'rare' really for any car I guess. You could try some UV dye in a charging attempt I guess to confirm it.

unless you have upgraded clutch and power, I'd think stock would be OK. If clutch has been upgraded, some stock forks will crack/fail. Some aftermarket companies make heavy duty forks.

maybe I haven't kept up very well but, could this be the crank pulley? Symptoms aren't a great match - could make the steering feel heavy while slipping.....?

That was the only code? how old are the plugs? what year vehicle? how many miles? have you owned it for a while or s it new to you?

is there a lot of red stain/debris on the hood above and parts near the compressor? that could indicate the clutch slipping.

I remember nothing about those sizes, but was gonna suggest Datsun convertible as my old SRL311 had a valve.

yep, check https://www.troublecodes.net/subaru/ for a list of codes.

yep, 22oz for the outback, I think my WRX is less, maybe around 18???

whoa!!!! My dad had one, I swear aircraft can land on that hood! It's kinda like driving a waterbed down the road. You can be doing 80-90 and it's just like doing 50. You look down at that weird speedo and go , yikes, better ease up.... parking it was a challenge at times.....

I have read several times that the H tube or orifice w'ever can make a 'hooting' noise in an overcharged system.

My 2 experiences was that I felt a little improvement. Not unexpected since new struts should feel better than old/worn ones? I have read that KYB claims new struts from them are 15% stiffer than Subaru's OEM spec. Not sure if that's across all years/models though.

i know it's random, but maybe at every opportunity, have someone start the car while you listen with the hood up for the location of the noise? i THINK IAC valves can buzz. Early 90s have had buzzing ABS pumps, but I don't think that will prevent starting.