myf150needshelp

Hi all.

I need help!!

My truck has a rough idle at the stop light sometimes and then it goes away. later on. my engine light comes on. I get the following codes.

2 CODES.

P0171

P0174

MIL ON

MONITORS

1 INC

EVAP

7 READY

MISFIRE

FUEL

COMP

CATLYST

02 SNSR

02 HTR

EGR

I looked up the codes and it says that both left and right banks are running lean. I already changed a bunch of stuff. Ok, this is enough for one post.

Anyone know what all the other stuff is?

thanks.

myf150needshelp

Truck is a 2001 f-150 4.2 liter engine.

oldmanb777

Fuel pressure regulator? Pull the vacuum line off, and see if it is leaking fuel into the vacuum side.

lafd0101

i had a problem with my 2004 5.4l stalling/rough idle, i have an after market intake. I pulled the throttle body and dscovered a lot of black greasy dirty film on the back side of the butterfly valve. a bit of carb cleaner and a towel to remove the film fixed the problem. Good luck!!!!!

stevelaramie

I had the same problem with the 5.4 and a cold air intake as well. The elbow was on a slightly off set angle and it caused me to idle like I had open headers and stall out at red lights.

myf150needshelp

a HEGO sensor.

my book says "HEGO sensor unable to switch".

what is it???????

Good old Bill

The 2000 thru 2003 4.2L has a TSB about the isolator bolts securing the plastic plenium chamber leaking causing the two codes. Its a pricey fix, about $150.00 for the parts. Takes a good 2-3 hours to do. Its not hard, just awkward to get at some of the crap. Note, the firewall sound deadener nees to be cut by the heater hoses for more clearance. Give me a PM if interested in more info.