1998 E320 MAF CEL

[Dealbreaker]

Had a water pump failure on a 1998 E 320, 208k mi. In the process of the repair, the airbox was removed, and the MAF was disconnected to move the snorkel out of the way. Upon conclusion of repair, the CEL showed up indicating a malfunctioning MAF. Car runs normally. No idle issues, no hesitation, stinky exhaust, or bad mileage. Tried a junkyard MAF, and also a new BOSCH unit. Every time the code is cleared, the light comes back on within several miles.
OTC scanner in DATA VIEW mode shows the fuel trims on each bank are 15.xxx and 17.xxx. MAF data shows about .33 lb/min at idle, and as much as 8.xx on the road (depending on how aggressive I drive). These are essentially the same readings for all three MAFs I have tried.

I have not inspected the snorkel feeding the throttle body for cracks or leaks. Everything else on the scanner seems ok. What else should I be checking? Wiring to the sensor seems fine if all three behave the same. I'm stumped. If anyone has seen this before, or has any info to add, I would appreciate it.
Thanks!