17544 - System too Lean Code. WTF ?

[Elberoth]

I just got the following code:

17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 001 - Upper Limit Exceeded

I logged for long term fuel trims (Block 032) and 1st field is 6,4% and the 2nd one -18,8% (negative).


Any ideas what may have happened ?

Vaccum leak ? Fuel pump ?

I have recently installed TP (got code for that, too), TIP and a new MAF.

Car feels normal.