long term fuel trim.

[Everything4x4]

Hey guys I have a 2000 ranger 4.0L and im stumped on this one. but first let me start from the beginning. I had p0174 and p0171. I did upper intake o rings and the gasket below the fuel rail. lean codes went away. but p0174 came back,did pcv hose which got rid of the code. how ever now my ltft1- is at 14-16% and my ltft2-is at 15-17% with no codes displayed. today hooked it up to the scanner and cleared KAM at initial start up both ltft's were at 0% but my stft's where at 20-25% and slowly dropped and my ltft's came back to the above percentages. I do believe I hear a vacuum leak which I think is coming from the back of the intake. so I brought up stft's pids and ltft's MAF IAT IAC o2's sprayed everything down with carb cleaner and no change in stft's nor idle change. another coworker had the a similar problem he put some rtv around the upper intake where its seamed together I no not a proper fix but we tried it to see if there was an improvement. while he was doing that I was visually inspecting for vacuum leaks found one hose that was damaged on the heater core control valve and fixed it. no other hose appeared to be damaged. Then we put the intake back on after a tb cleaning and ltfts are still 14-17% ,any idea guys? I might just take it to someone with a little more experience than I since it is my daily.