Less power than it should/bogging motor?

Hello, it sounds like the Catalytic Converter may have failed and is restricting the exhaust. Here are some guides to help. Converters will fail when there is an overly rich air/fuel mixture, or if the engine is burning oil and it causes the Converter to overheat it will melt down, and/or break apart and clog up the exhaust. We will usually do a back pressure test at the front oxygen sensor opening with the sensor out to see if there is excessive back pressure. I will also put a borescope down the exhaust if possible and physically look at the catalytic converter to see if it's melted down, as well as take some pictures for the customer to see. But the guides below will help. Read through the low power output guide as well.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

https://www.2carpros.com/articles/symptoms-of-a-clogged-car-exhaust-system-a-comprehensive-guide

https://www.2carpros.com/articles/engine-has-low-power-output

I measured the temperature across all parts of the exhaust. There are many, first one up front immediately after the exhaust, and then there is one which i think is the 2nd catalytic maybe and then there is a square box looking one and then the muffler.
First and second pictures are for the before and after the exhaust immediately coming from engine, which i believe is the first cat
Second set is for after and before the muffler
3rd set of pictures is for the box looking thing which goes to the muffler. There is some steam out of the exhaust but doubt it's enough.

Made a hole here like in the picture and this is the pressure i got. Made a video showing all the temperatures around the system to make it easier for you. I don't know why there are so many components. I really do not like working on these types of issues when so many components are involved.

Hello, I apologize for the delay, did you drill a hole in the exhaust to get that back pressure test? I have the diagrams of the exhaust system, there are 2 Catalytic converters. But this 8psi reading, it this at idle? and where is the hole location, is it up near the front oxygen sensor location?
Is that converter glowing right there? the 8psi back pressure reading is way too high. 1 to 1.5psi back pressure is the max. That thing looks like its glowing red, I wouldn't drive this vehicle anymore until you can verify that cat. I have seen vehicles catch on fire because of this.
The 2nd diagram shows the 2 converters colored in orange, the green are just exhaust heat shields.
If you unbolt the back of that converter in the 1st picture I think you're going to find that chunk of the converter is melted in one solid ball and blocking off the exhaust right there.
But you need to figure out why the cat failed, if you have a scan tool, take a look at the live engine data and check the Long Term and Short-Term Fuel Trim numbers. Right now, they are going to highly skewed due to that cat.
Once you check that exhaust, and you're going to have to check the rear catalytic converter as well, if they have both failed and they are replaced. Then when the vehicle is running ok again, look to see if those Fuel Trims are positive or negative, (for example LTFT-STFT +/- 10% or more) that needs to be corrected or the new catalytic converters will fail prematurely.
Let us know what the condition is of both cats, and then we can figure out why they failed so bad.

While idle. I drilled a hole immediately pass that big catalytic u marked with an arrow. Can you recommend a place where i should drill? Ill check the red glow i didn't notice any.

Nothing glowing. Here is where the hole is. The hole is toward end of the first catalytic. Temperature at 1 is 600, at 2 200, and at 3 400.

I posted more information if you refresh this page and look at my last post. But you should just remove one of the front oxygen sensors to measure back pressure instead of drilling holes, because with the measurement you took, you're measuring after the first converter, so you need to check in front of the first converter. Just remove one of the front oxygen sensors long enough to take a quick back pressure reading. It doesn't need to be running long. With 8 PSI, that's reading back pressure in between the 2 converters, I think you'll find even higher back pressure in front of the 1st converter.
If you unbolt those bolts that the white arrow is pointing at, you should be able to see into the back of that cat, it looks like both might be melted down.
Do you own a borescope camera?

But if i remove the o2 how will i measure the pressure at that big of a hole? Or you mean measure it same hole but with the o2 out? Ya removing those bolts won't let me see the inside i have to remove the exhaust back enough i think to drop it.

Well using an adapter that can fit the 02-sensor hole is the way I would test it, that way a back pressure test can be done without drilling holes into the exhaust. In some cases, if you work in a shop, you'll need to be able to test the back pressure of a vehicle to verify the cat is not at fault in certain situations. They sell back pressure testing kits, or you can make an adapter out of an old 02 sensor. You only need to get a quick reading, just don't use anything rubber as an adapter, I've seen someone do that and it melted, then the piece fell into the exhaust on top of the converter inside. It was not good.

Another way is using live engine data and input the numbers into a VE calculator such as the screenshot below, you just find a road where you can do a wide-open throttle run while recording the live data. It only needs to be until you hit the highest rpm and then let off the throttle. Input all the data PIDs at the highest rpm achieved, and the "EST_VE" percentage reading is the Volumetric Efficiency of the engine, or how well the engine can take in air and let out exhaust. With a clogged (restricted exhaust) the VE number will be very low. Meaning that either no air can enter the engine, or no exhaust can escape the engine.
It is a very effective and fast test to see if there is a bad cat. Below is a link to the website with the test on it.
And one other method is using an oscilloscope with a pressure transducer screwed into the spark plug hole. The scope waveform will show high pressure on the exhaust stroke of the engine. The 2nd diagram below is an example of an in-cylinder pressure transducer reading, you can see the 2 compression stroke towers on each side, and the area where there would be excessive back pressure shown if there was a restricted exhaust.

https://atgtraining.com/atg-volumetric-efficiency-calculator/

I can't do any of these lol. Let me see if i can find a cheap o2 adapter on Amazon.

OEMTOOLS 37263 Exhaust Back Pressure Tester/Gauge, Catalytic Converter Test Kit, Exhaust Pressure Tester, Catalytic Converter Test Kit, Exhaust Tester https://a.co/d/aRR1n8r

This works?

well, you can try that one, but you already have a gauge, so really just coming up with an adapter is all you need. This is one I made out of an old oxygen sensor, and some JB Weld.
I wouldn't pay $60.00 for that kit. The gauge you have works great. And once you have an adapter out of an old 02 sensor, you'll have one for testing in the future. I build just about as much tools as I buy. As for the current vehicle, I'm sure you want to get it done and out of there. So, your 8 PSI reading already tells you that the 2nd converter has too much back pressure. That alone already shows that you need to check it, and dropping the exhaust from the back of the first converter on a Subaru is easy. You just need a 2nd person to help you lower the entire thing once it's unbolted. I worked for a Subaru dealership, and you can take the entire exhaust down pretty easy. That way you'll be able to see into the back of the front converter. I'm sure if the rear one has failed, the front one went first.
In the 2nd diagram below, you can see that your test location right now is measuring the mid-section of the exhaust's back pressure to the 2nd cat. So, if its that high at that location, it's going to be even higher in front of the 1st cat. 8 psi is extremely high, and if you revved the engine the back pressure would go even higher. Thats why the vehicle had no power, you could probably hear the back pressure hissing while driving I bet.
Something else you could do real quick is pull the front 02 out and just see if the engine revved up better, because all that pressure would have a place to escape. It would be loud, but you would be able to slam the throttle open and get a response from the engine.
I would put a bore scope down there and look at the front cat if you don't want to drop the exhaust yet. But you already have enough proof to do so. You could buy that kit too if you needed, I think there are cheaper ones though. I use a Harbor Freight Vacuum gauge, because they also go up to 10psi which is perfect for back pressure testing.

But those seals are going to melt being in the exhaust, not sure why they would put those on there, lol..

I see. Thanks for being descriptive. I have a ton of tools. O old o2 lol. No time to start inventing and be MacGyver lol. Four kids and many cars to play with. I'll get a kit from Harbor Freight quickly and see what i get. But I'll remove the o2 first and see. I thought about it.

If you work on a lot of vehicles, it is worth investing in a bore scope, I use mine to look into exhausts, in cylinders for burnt valves or leaking head gaskets, there's many uses for one. But I also know tools are expensive for sure. Let us know what you find with that cat.

I think this looks okay. From removing the first o2.

Can you see from the front a bit more? Being able to see through the substrate? From that picture we can at least see that its not broken up, they are showing #13 as the Rear Catalytic converter, but have no 02 sensor behind it. And that section of pipe from the Rear Oxygen sensor (which is only for the front Cat) is a pretty long stretch, will your bore scope reach that far?

meaning I have to remove the 2nd o2 and then scope it to the rear cat?

Well, we need to know why the back pressure was so high, and with no oxygen sensor behind the rear cat, it looks like it's not monitored by the ECM. Are you sure that gauge you were using is accurate? They are listing it as the rear catalytic converter, although it might not be a 3-way catalyst, but it's there to finish off any HC or CO that gets by the first cat.
With no codes to go by, it's either that the back cat is bad, or the valves are way out of adjustment on this vehicle. The valves are adjustable in this engine, it looks like they are adjustable the same way a Honda is, which a locking screw on the rocker arm.

I am guessing the gauge is okay. I will remove the rear and see. Once i receive the new bore scope tool I'll check it all out.

It looks like the valves on a signal overhead cam are adjustable by a lock down screw, but the dual overhead cam, the valve lifter actually needs to be measured like a shim to adjust the valves, those are a pain. But I'm sure you would be setting misfire codes if the valves were that far out of adjustment. Let's hope it's the rear converter.
How did the front 02 look? was it covered in soot?

No, it looks good. And yes, i have no noises from engine or any codes. Just a reflex of noise around the air filter suggesting something is blocked. I am done with Subarus after this. They always have issues.

Yeah, they are difficult to work on being a box engine, we used to just pull the engines to do the head gaskets, there was a huge head gasket recall back in 2002 I think it was. As well as a Recall for ECM programming, I must have reprogrammed 500 vehicles, lol. But i agree the new ones are really difficult, especially with the huge timing chain on the dual overhead cams, that was 20 years ago too.
One other thing I was thinking of is checking the MAF sensors g/s (grams per second), it should average around the size of the engine. So a 2.5liter should roughly be around
2.8-3g/s at idle.
Try the VE test as well, on the website page for the test at the top it gives instructions on exactly how to do the test. It can save a lot of time when diagnosing low power issues like this with just scan data. And give you direction to test pretty fast.

What do you input for RPM?

The highest RPM you hit with a quick wide open throttle run. You record your live data and input the numbers that occur at that highest RPM. That way you're getting the max load on everything. The scan tool should be able to record a certain amount of time, and then just scroll through the live data until you come to the highest rpm achieved, stop there and use all the data sensor numbers from that point, if that makes sense.

Do i need to drive it or just at idle or in drive?

Yeah, you need to find a back road somewhere you can do a wide-open throttle run, just once and record the data. The instruction on the page explains things, you have to be moving so you put a full load on the engine to get the max air flow it will take in and that's how it calculates the maximum volume of air the engine can pull in.

I scoped it and i think it looks okay. Removed 2nd o2 and looked then scoped it from there to the 3rd piece which is maybe the 2nd cat.
1st picture is from 1st o2, 2nd is from 2nd o2 so from front of 1st cat.
3rd is pipe in front of 1st car leading to second car.
4th is second cat.
5th is also 2nd cat.

The 2nd picture looks a little odd. But if that reading of 8psi back pressure is correct, something is not right. I would go through and do the full VE test to see what kind of numbers come up. With nothing setting any codes and the extreme lack of power you described, we need to know if there is correct air and exhaust flow. Even the MAF sensor will tend to read low with a converter issue, less air is going to enter the engine if the exhaust can't escape. I don't really rely too much on temperature tests for converters because it's just not a definitive answer. But a VE calculation will give you more of a direction. Something is causing that high back pressure. There shouldn't be more than 1.5 to 2 psi of back pressure. Has this vehicle had the cats replaced before? Meaning is there possibly broken up sections of an old cat stuck in the muffler? Some shops forget to check the rest of the exhaust system after replacing a broken-up converter, and pieces end up downstream in the exhaust.

looks like the cats. I will put back the first o2 and measure pressure through o2 hold using the o2 adapter I ordered. then I'll put everything back, close the holes I made with the pallets that come with the pressure gauge and check MAF and VE after.

okay, sounds good. Let us know what you find. I'm surprised they don't have an oxygen sensor behind the 2nd cat. Service info clearly calls it a rear catalytic converter.

Maybe the second o2 which is way before it serves the purpose, i just don't know how.

They just do all their fuel corrections with the front cat.

Here is what i have at the front or 2nd o2 after the first cat using the gauge inserted into the oxygen sensor hole.

Yeah, that is still way too high, you can see with the tool, they even show the max limit of back pressure. Thats what is causing your bogging down and lack of engine response. Even at 2psi I worry. Glad you got the right kind of kit though that will come in very handy in the future. But I think you should drop the exhaust from the bolts at the rear of the 1st converter and see what's going on. You have a lift to work on, so that's a huge help. Most of the time I'm working on the ground during mobile calls.
Did you try raising the RPMs as well, and did the back pressure increase?

Did not try. I can, let me raise RPMs and see. Also keep in mind i still have the 2 holes i drilled open, so pressure should be even more.

Even so, at idle it's too high. it looks to be reading about the same as from behind the front cat, so it has to be the rear one. But once you unbolt the rear of the front cat, have someone help you just lower the entire exhaust, they are easier to take down that way. That's how we would do it at the dealership.

Here is while running and revving.

1st cat and the pipe after it.