Gradual loss of power in 2000 EVC

[xEVC]

I have a 2000 EVC that I've owned for 15+ years. It is my impression that over the last decade or so, there's been a subtle loss of power.

I notice it on a few big hill climbs in the Sierras where I used to do at 60mph without strain, and now 50mph feels more natural.

The van otherwise runs great, passes smog, MPG seems pretty consistent, and has no CEL or codes.

It's possible it's all in my mind

Recently Completed Maintenance
* timing chains
* plugs, wires, and coil pack
* air filter
* transmission filter & fluid

Possible culprits:
* partially clogged catalytic converter
* fuel injectors
* gasoline? I run 91 octane gas, but maybe there is more ethanol now than in the past?

Any ideas?
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[SambaBurnsRed]

An engine is an air pump. Moving air = power. There is usually enough fuel available, if not it would start to buck or miss.

Catalytic tech has improved a lot in the past 25 years. So going to new catalytic and if rusty, exhaust system should give you a boost in flow.

I put new catalytics in this Range Rover, and it turned into a beast. Was going to sell but decided to keep it, and turn it into an overland machine. So much fun to drive with that power on tap.

https://www.instagram.com/reel/DFOhZ99ScXf/?utm_source=ig_web_copy_link&igsh=MzRlODBiNWFlZA==

[paddygarcia]

Converter is a good thing to check. Injectors are another.

I sent the injectors out for cleaning on what I thought was a good-running 2003 with 145k miles, it turns out that one was fully blocked, one fully open, and the rest clogged to varying degrees. Similar results on a good-running Porsche 911 that I refreshed.

They're underneath the intake manifold so unfortunately it's a production to get them out.

[EuroTec]

+1 on the cat suggestion.
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If it ain't broke, don't fix it!

[xEVC]

Great ideas all, thank you.

* injectors can be had for $650 for 6 at europarts-sd.com . I've watched videos on replacing them, and it looks difficult, but something I could manage myself.
* a CARB-compliant catalytic converter is $750 to $1300 at magnaflow.com (? not even sure there are any available for my 2000).

Seems like an expensive way to do "reconnaissance by parts"

I have VCDS - are there any measuring blocks I could watch that would diagnose this?

Also, what about the Mass Air Flow (MAF) sensor : I don't know if mine has ever been replaced.
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[paddygarcia]

MAF isn't hard to clean, worth a try I guess?

If you go the injector route, RC Injection will clean and rebuild 6 injectors for well under $200. IMO a good rebuild of original parts is better than new parts these days.

[TheOneTrueQuux]

[SambaBurnsRed]

Regarding injectors, most old, high mileage engines will have passed a lot of fuel, so they will be dirty for sure.

My boat engine injectors were a mess, it was hard starting & smelly (leaks, low fuel pressure, partial spray pattern) but I did have decent top-end power.

[mikemtnbike]

I know it's might be snake oil/placebo effect, but I feel like annual use of Techron (kind of the most reputable FI cleaner product)has helped my van run more smoothly
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1991 Vanagon GL 2.1 AT Westfauxlia. "Frankie" Totaled https://www.thesamba.com/vw/forum/viewtopic.php?t=764510&highlight=carnage
1995 Eurovan Camper "Marzivan"
2020 GTI SE manual

[Abscate]

Check the cats with a back pressure measurement.

Clogged fuel injectors would P0174 code on at least one bank.

It’s not the gas.

Tire pressures up to snuff?
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🇺🇸 🇺🇸 🇺🇸 🇺🇸 🇺🇸 🇺🇸 🇺🇸 🍊 🍊 🍊

[xEVC]

Is the catalytic converter back pressure easy to test? I've never heard of doing that.

More info:
* Injectors: could purchase a new set for $650 or get the originals cleaned for $200. I have read a few reports of the OEM injectors plastic electrical connections becoming brittle over time, so this might lean me towards new vs. refurbished.
* I found a much cheaper ($500) California (CARB) Catalytic converter from busDepot here: https://www.busdepot.com/023131089dx

I did some test drives this week running VCDS, and everything looked pretty good:
* Group 025 Oxy Sensor before Cat showed -3.1% (regulation), 4.7% (adaptation partial load) and -2.3% (adaptation idle) - I believe these are all great numbers, being within 5% of zero.
* I did some hard accelerations watching group 045 (Knock Control Cyl 1-4) and Group 046 (Knock Control Cyl 5-6) and all stayed at 0.0 degrees. No audible knocking heard either.

My thinking now - the van is really running pretty good, and I may just run a bottle of Techron through it and drive it this summer, and save the parts cannon for later...
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2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels

[xEVC]

Forgot to mention this:

On my 2000, with VCDS, Group 009 and 010 show this:

[xEVC]

I decided to replace all 6 injectors. Not exactly on a whim, but based on my gut feeling that since everything else seemed to be working well (timing chains, spark, O2 sensors...) that fuel delivery was suspect.

I'm working on a detailed writeup, but the most amazing find was:

Injector Turd

this chunk of something popped out when I flushed the fuel passages after separating the intake manifold and removing the injectors.
_________________
2000 Eurovan Camper (Winnebago)
Upgraded with 16" wheels