check engine light

i know what the code meens but i dont know the cause. i have a 96 2.0L the code is PO171 bank 1. i have results for the test

"Diagnostic Trourble codes PO171 Bank(1) (cylinder #1) indicate the fuel/ air ratio is too lean. the fuel adaptive system is at the rich correction limit."

now i checked my lines not clogged or frozen. (its very cold) i used inject cleaner and dry gas but no change. i think it is my fuel pump, but i dont know.

any advice?
thx

IIRC, the 171 code relates to a dirty MAF.

ok thx

IIRC, the 171 code relates to a dirty MAF.
And if the MAF sensor is clean then what? All fuel related sensors are operating within their parameters with no other codes coming up and fuel pressure is a steady 35psi. Sprayed and sprayed (WD-40) the intake and associated vacuum hoses and still no luck. Don't have a smoke machine to test for leaks but come on if the spray won't make a difference it can't be that much of a leak. I'm just about to give this thing back to the owner but I know he needs it to pass Emissions test and it won't with this crap going on.