[highmilage4runner]

I am new here but a long time lurker. I cannot start a new thread so I thought Id take a shot asking here. Recently purchased a '02 4 runner 4wd limited with 328k on the clock. Started to have a slight hesitation at highway speeds from 2-3k rpm. This progressed and got way way worse to the point it cannot go up hills anymore. Cannot rev past 3500 anymore unless the A/F sensor is unplugged. Idles fine, and is recently taking a longer time to crank.
Things that have been replaced or swapped with no change
Plugs
coils
wires
MAF
A/F and rear O2 sensor (both OEM)
Entire throttle assembly (TPS, throttle motor, etc.)
Crank sensor
According to first dealer Compression and fuel pressure are perfect.
No vaccum leaks
CAT allegedly is good but I may check again.
Timing belt water pump and all tensioners were done in last 25k miles.
ECU swap with programmed unit from flagship one.

Of note: it does not hesistate in limp mode. When in regular mode it smells like straight fuel out of the exhaust. Running extremely rich. Out of limp mode it will rev and then drop 300-500 revs like someone took their foot off the throttle.

The issue progressively got worse.
Im down to about 40 hp or less these days. Shop and dealer have no idea what is happening and have never seen anything similar.

Does anyone know something else I should try/test/check that could cause this? Dealer said car is mechanically perfect and they're quite confused.

Thanks,

Wyatt