2002 Accord, low power on hills

[bobwhite]

2002 Accord F23A4, auto, low power on hills and fishbite roughness on flats.
No CEL, except for sometimes P0420, cat efficiency.

187K miles, well maintained, one owner (me).

Last year it could climb a certain 8% hill in 3rd gear, 50mph.
This year, same hill, it shifts down to 2nd gear, 40 mph.

Also noticing fishbite roughness on flat roads at steady 40-50mph.
Cruises at 75mph well. Idles well. Never overheated,

Not sure if it's a motor issue or a tranny issue.

Here's what I've done:

compression test - 180/170/185/180
vacuum test - 20" steady at idle, does not drop at high rpm
exhaust backpressure test - 1.5psi at 2500 rpm

adjusted valves - they were about right

fuel pressure - 44psi at idle, 50psi at higher rpm
I did not check fuel pressure when driving up the hill.

Air filter is clean.

New NGK plugs and wires (they were due for replacement)
New Honda distributor cap and rotor (also due)

I checked the 2 dual trans solenoids.
Linear solenoids were clean and within spec for ohms.
Lockup solenoid screens were very dirty, I cleaned it out. Ohms in spec.
Did not check the lower 2 single solenoids.

Changed the trans fluid with Idemitsu type H-plus, 3x drain and fill.
Old fluid was not bad, I've done 25K mile drain and fill for a long time.
A little material on the mag drain plug.
Today I added a tube of Lube Gard Transmission Lubricant Instant Shudder Fixx, did not seem to help.

I have not checked the egr valve/passages or the injectors.

Running out of ideas.
Comments are welcome.

 

[BlkCurrantKord]

Explain "fishbite roughness" I've never heard this term before.

For curiosity sakes, do you have a temp gun to see what temps the manifold is at or exhaust?

 

[bobwhite]

To quote Mr Google:

A "fishbite" misfire is a very subtle, quick, intermittent engine hesitation or jerk, often felt during light acceleration or cruising, mimicking the feeling of a fish nibbling on a line.

No, I don't have a temp gun.

 

[bobwhite]

I replaced the cat, and the car runs like new.
I got a Walker cat for about $500. Honda wants $2300 for theirs.
Living in NY, it needs a CARB cat, which is a lot more expensive than a Federal cat.

I rechecked the exhaust backpressure by revving the throttle from under the hood.
The old cat went up to 9psi, the new one maybe 2psi or less.

 

[BlkCurrantKord]

Walker typically makes a great product. I was already somewhat leaning towards it possibly being a clogged converter, which sounds like it might be.