P0171 and p0174 5.0

[Bboy]

I have a 5.0 swapped ford ranger, engine and transmission came out of a 98 explorer. I've been driving it for over a year since the swap but lately I've had a check engine light for p0171 and p0174. Before the check engine light came on the transmission started feeling like it was slipping and when I get on the throttle the torque converter just spins. I cleaned the maf sensor (didn't notice a different) and I was already planning to do the fuel pump before this problem, so I did that, with the new fuel pump I reset the check engine light and my transmission "problems" went away as well as my hard starting that I've been dealing with for a while. Now yesterday I took the truck offroading (5 days after fixing it) did some rock crawling and went through some puddles, afterwards my transmission started feeling like it was having the same issues, my truck got harder to start, and then 10-20 miles later the check engine light came back on for the same thing. I should mention that since doing the fuel pump I've put almost 300 miles on the truck before the light came back on, I should also mention that the first time I filled the tank after doing the fuel pump it leaked out the top were the plastic ring is but hasn't leaked for the fill up before or after the offroading trip.

 

[410Fortune]

What brand fuel pump did you use?
Did you change the fuel filter?

I think you should do a fuel pressure test

P0171 and 174 has both banks lean
Look for air leaks in the intake that effect both banks, throttle body gasket, egr gasket, missing vacuum line, bad plenum gasket, etc
Usually a leaky intake after the mas air flow sensor
Also you need to do a fuel pressure test

What color are your 5.0 injectors?

A leak at the fuel tank lock ring is not good!you
May want to raise the bed and check it out

 

[BUXTER]

I say Vacuum leak.