2017 drive 2 running rich

[whistlebritches]

Engine will foul spark plug in approx 2 rounds of golf. Being EFI, I checked fuel pressure (38 psi). Checked valve clearance, found them to be looser than spec. Adjusted per service manual. I have a Yamaha EFI Diagnostic tool that fits these cars and hooked it up, didn't find anything outside of normal. Intake pressure sensor reads 99 with the engine not turning over, then as you hit the throttle pedal to turn the engine, the readings drop from 99 to into the 70's quickly-probably quicker than the tool can display it. Every once in a while it'll show above 100, which I believe may be normal? EOT shows normal, it's about 85 in the shop all night and this morning the tool displays 85, same for the intake air temp. I also pulled the throttle body off and inspected the injector for leakage. With the pump holding pressure, there is zero dripping from the injector.

There were no trouble codes displayed on the tool and never has had a check engine light.

Got me stumped. Got any ideas?