2000 210.065 code help

[jstbecauz]

I have a 00 E320 with two codes, P0171 and P0174. After resetting it may take up to 3 cycles and 50 miles to return.

Vehicle has 40,000 miles on it.
Vacuum at MAP is 19hg although reading it through the MODIS Global OBDII it states that it is 10hg, but voltage test proves it is in range.
Fuel Pressure at idle is 54lbs
Fuel Trim at idle is good until you drive it then the long and short trim slowly creep up to 27 and 29 and will stay there until it is reset again. It will never settle back down and will trigger the light at this point.
MAF is 4gms to 5gms at idle - again through the MODIS Global OBDII
O2's are working properly all the time.
No intake or vacuum leaks, and no misfire condition is evident.

Vehicle runs excellent...am I missing something? Is the Global OBDII interperiting the information incorrectly?

[jstbecauz]

I made a mistake, the short term fuel fluctuates properly but the long term keeps creeping up.