P0171 Bank 1 Lean code nightmare!

[512SVT04]

I've had the good old P0171 Bank 1 Lean code for a couple of years now. I've tried replacing the vacuum line that goes to the back of the s/c, pcv, o2 sensor, fuel filter,tested for intake leaks, and cleaned the intake/tb all with no luck.

I would assume if it was a cat I would be getting other code readings. It has passed smog (If you drive @55 for 30 miles it will reset all categories except the EGR which doesn't kick the light on until complete)

Where do I go from here? It's weird because it's only bank 1, not both sides of the motor. Should I try changing the fuel injectors?

If anyone has had this specific problem and fixed it after the above mentioned please let me know what you did!

It's a 2004 Lightning with 160k on it.

Thanks!

 

[Dusten]

Lean on 1 bank is generally post intake. I'd datalog the truck and look at fuel trims on both sides. Check for exhaust leaks.

I wouldn't assume fuel injectors, but you can swap them sides and see if you get a p0174

 

[PHX396]

Check where exhaust mounts to collector. I have had a slight exhaust before and it pulled the code. I checked collector bolts and they were loose so I had a slight exhaust leak causing the code. Check it if you haven't since you checked everything else.

 

[mizlplix]

You didnt say but if you are running long tube headers, wrap the pipes from the rear of the second cat up to the tube bend at the head.

OR drive the truck 30 minutes, then jump out with motor idling.
Shoot the cats on both sides to compare temperatures.

Miz

 

[512SVT04]

Update: I changed out the EGR and it seems to have fixed the issue. It did come on onetime under hard acceleration, but after clearing the code it hasn't resurfaced.
Thanks for the help everyone!