You can see the small spring loaded plungers in the side of the top part of the lifter. When in normal operation the plungers engage a groove in the lower part of the lifter. When the computer shuts off 4 cylinders oil pressure hit the hole in the lower lifter and pushes the plungers inward and out of the groove then the lifter collapses and injector shuts off.
The tarnish had built up and stuck the plungers inward and had it throwing codes and running like a turd. I eneded up pulling both heads and replacing 3 lifters and took the other 5 stupid lifters apart and give them a good cleaning.
Got it fired up and she runs smooth now and will promptly get the AFM turned off.
They say it saves 5-7% on fuel mileage......figures up to aboutn$5-600 probably.....cost at least that to fix it....and that was me doing it.
So run damn good oil and change it!
The cylinder walls looked amazing for 200k miles considering the varnish in it....it did get a real good douching and flush with brake clean.
So there's a little FYI for today.