Rep Power: 0

So I left today for a 500mile round trip. Car ran great until about 200 miles in. I just bought this thing 2 weeks ago. 2001 EX 5 speed...only 113k miles.
Let me start by saying whenever I buy cars...preventative maintenance is a big thing I like to get caught up on.
I changed the oil with some Mobil 1 5w-20. And tossed in 8oz of the Engine Restorer in the crankcase. The previous owner said the car burn's a small amount of oil every oil change interval, maybe half quart in 3,000 miles. Nothing terrible. And I've always had good experience's with the Engine Restorer in helping aid burning oil. However this is the first vehicle with variable valve timing that I have ever ran it in. But after reading around, I found it to be safe.
I also poured about a third of a can of seafoam into a full gas tank of Chevron 91 octane. Drove the car around 100 miles between the maintenance and my trip up north. Everything was fine. In fact it idled smoother and over all felt better. Again, the Engine Restorer stuff in the grey can, is amazing in my experiences.
Fast foward to today. I was clipping along at 60mph, right at 3k. That's about the top speed I like in this car. (First car with a higher final drive ratio. Don't like the idea of the rpm riding much higher than 3k for long periods of time). I get about 2 hours into my 4 hour drive and notice a huge lack of power in 5th gear. At 3k rpm I give it gas, engine noise gets deeper, but no noticeable acceleration. No rpm rise, not like the clutch is slipping. Got to the top of the summit. And the engine drive's and operates fine again. I can floor the pedal and it takes off like it should.
Halfway back home and it starts to severely show signs of no power. I have semi trucks passing me as I'm struggling to pull a 5% grade, going 50mph in 4th gear at around 4k rpms. The more I push the pedal down, the more the cars lugs down. By this point it's even having a hard time on flat pavement. I pull off, check the oil, check the coolant after its cooled a bit, I even pull each individual coil pack and ensure the pigtail is connected and the packs are securely seated on the spark plugs. As well as disconnect the injector pigtail connectors, spray them with electrical cleaner and reconnect them.
Get in the car 10 mins later and I take off in 1st. Same damn thing, it struggles to get up and go. Even in 1st/2nd gear. I push down the accelerator, engine noise gets super loud and bassy sounding almost, but no normal acceleration. Super luggy.
I get on the interstate after wrapping out 2nd gear to get upto speed and just like that...it starts with the full power and acting as its supposed to. Stays like that for almost 20 miles. And then boom, same as before. Struggling to stay at 60mph on the slightest uphill or flat ground with a headwind.

I'm stumped. I'm new to Hondas. Anyone ever have bad experience with seafoam in the gas? Is it possible that seafoam could have dislodged or stripped gunk from the tank or lines and clogged a filter or injector?
No CEL or warning lights are present

 
Rep Power: 134

Jeez could be anything to do with the fuel, spark or compression that an engine needs to go. I will mention you should have the timing belt, water pump tensioner etc. replaced if they have not been done yet. Common issue with these engines is a failing head gasket so look into that. Is the clutch still good? I remember losing the ability to engage 5th gear when my clutch needed replacement.

 
Rep Power: 0

Timing belt, timing components and clutch were all replaced in the 90k's mile range.
It's not that 5th gear isn't engaging....it that it has no power once it's been running for awhile. Even when I was almost home yesterday we stopped at a light, I started off, let the clutch out and put the throttle down, and it was barely getting up and going. Engine noise got deep and bass sounding, but not acceleration.

 
Rep Power: 222

cat clogged?

 
Rep Power: 0

Unfortunately that's what I'm leaning towards at this time. I'm going to put the car up on ramps today after getting it warmed up on the freeway, come home and check the temp at the inlet and the outlet of the cat. Maybe pull an 02 sensor, pre cat, and see what that does.
It's really going to sick if that's the issues. I live in CA and they're spendy.

 
Rep Power: 518

I might suspect exhaust restriction

Got fault codes? Does the check engine light even work?

 
Rep Power: 0

No CEL. And yes, it is in working order.
Starting to think exhaust restriction as well. I almost don't even want to bother cleaning the EGR and pulling plugs to inspect them.
I am now developing a rattle underneath. Different then my heat shield rattle.
This rattle sounds like small pebbles in a tin can.

 
Rep Power: 518

So you didn't check for codes?

.

Bang on the pipes with a rubber mallet
Chunks of broken cat (or chunks of metal) can move around inside the exhaust causing clog type problems without consistency

 
Rep Power: 0

I did check for codes with my obd2 scanner. No codes were found. Which i found surprising seeing as how it's showing such lack of performance. I'd imagine a CEL to pop up.

 
Rep Power: 518

If the cat came apart internally and it's now impossible to drive the car normally (carry out a complete OBD2 drive cycle) , the PCM might not be able to complete two failing cat self tests in a row to set a permanent code. Check for pending codes and check OBD readiness monitor status, but that may not be of any help either.

 
Rep Power: 0

I'll check both of those. Thanks.
You mentioned "two" failing cat self tests. Are you saying there are 2 cats on these cars?
I only see one. Right after the down pipe.
The car has a DC header and full magnaflow exhaust with the magna hi flow cat.
When searching for cats online...I came across what looked like a cat that originally went in place of the now aftermarket header

 
Rep Power: 518

Nope. Study up on OBD2 code set criteria, you'll learn many faults must be detected more than a single time in order to illuminate the CEL.

Figure out what's really wrong first.



There were two different original exhaust configurations for the 1.7 engine,
Exhaust configuration depends on which version of the engine the car was equipped with from the factory.

D17A1 (non-vtec) had the cat built into the manifold

D17A2 (vtec) had a 'header', with the cat located further downstream

 
Rep Power: 0

This being an 01 EX....I guess it's safe to say it's the A2 configuration.
Just got up underneath. The cat it rattling like crazy as I hit it.
Also took my infrared laser temp gun to it. The inlet and outlet arent what they should be. Think it's safe to say, clogged cat/broken honeycomb

 
Rep Power: 518

Now....disconnect the pipe from the rear of the cat and figure out where all the broken pieces went

 
Rep Power: 119

Just tossing this out there..

I would be very interested in actual fuel pressure when power loss occurs.

Blown out cat can have a “chunk” that gets bounced around and blocks the flow interminably, but also a worn out fuel pump may work well enough until it been running for hours.

 
Rep Power: 518

FWIW I'd read (or record) O2 data in a scanner data list when the engine acts up, then I'd know whether or not fuel delivery is an issue to look further into.

 
Rep Power: 0

Precisely. I got underneath and hit the cat a few times with a closed fist. And sure as ****...sounds like a soda can with a handful of rocks in it.
Got a OE Walker brand Cat on the way.

 
Rep Power: 119

When you change out the cat, pull the entire system off.
Your going to have those “pebbles” in the resonator and likely muffler and might be able to shake some of it out.

 
Rep Power: 0

I'm taking it to a shop. I don't do the woke exhaust clamp thing. And I don't burn metal. So I'll have somebody with a good welder and steady hand, install this one.
But I will definitely pass this little tid bit along to the shop I'm taking it too.