Has anyone had this problem before? My 2002 F150 (50,000 miles) 4.2 is surging when cold. I just got done replacing the pcv valve. I noticed it was running better so I cleared the service engine light, but now is surging when the engine is cold. I live in FL so it does not get that cold like up north.
The following codes were the ones that the pcu put out, P1131, P1115, P0174 and P0171. I am leaning towards changing the IAC valve and maybe the oxygen sensors. Any help or input would be greatly apreciated. Thanks!

 

Well two of your codes are oxygen sensors on bank 2 code po174 to lean and code po171 bank 1 to lean. Code p1115 intake air temperature b circuit high output. Your other code is your oygen sensor code too. Try cleaning your mass air flow sensor and your temperature sensor first with some qd electronic cleaner from your autoparts store see what happens you might get lucky. Good luck hope this helps.

 

Vac leaks!!!

 

You have 2 separate troubles.
The 1115 is an open Intake Air Temp sensor.
Did you forget to plug it in after your work?.
The 1131 is caused by the 171/174 fault. The fault is an air leak into the intake.
The V6 is famous for intake manifold isolator bolt issue but it could be a hose or fitting.
It's not the IAC.
The fuel tables are shifted so far it affects hot idle and low speed drivability.
Good luck.

 

Guys. This thread is over 10 years old!

 

I want to offer this position about old threads.
When people search for info about their issues, old threads often come up.
The truck, motor and problems are still occurring for owners.
As I reads the original post and replies it became apparent that code interpretation was lacking some.
In the interest of adding to the thread that may be viewed by other, I expanded on the codes and what they mean.
Having said this, I do not feel an old thread is a waist or has no value to some one who may need the added information at some much later date.
If it can be accessed, it should have value if possible..

Good luck.