Went to Autozone and pulled these codes. I'm running too lean on banks 1 and 2. Can a fuel filter cause this, becuase after I had my fuel filter and oil changed the SES light came on. Is it possible to use the wrong kind of fuel filter?

 

I'm not sure about the Lightning motors, but on the stock 5.4 there is small elbow coming out of the back of the manifold that connects up to the PCV hose. This elbow will deteriorate and cause a vacuum leak that will throw those two codes. If that isn't the case, I would look elsewhere for a possible vacuum leak. Good luck and definitely post the results once you determine what the cause was. This will help others that may run into a similar problem.

 

It's possible to put it in backwards--against the flow. Should be flowing to the front--see the 'arrow'.

Dan

 

maf issues throw that code as well. Did you change or upgrade your maf at all???

 

Yes make sure the arrows pointing in the right direction.
Also MANY have been given the wrong filter, I've seen many post about that. "I think" the wrong is shorter "I believe" ?

But yes a filter or clogged injector, or bad gas can make it go lean.

Good Luck, let us know how you make out

 

I've upgraded to the 90mm mass air about 10 months ago, and yesterday i took it out and cleaned it with brake cleaner and let it dry, but didn't help. The SES light comes on after about 50 miles after you clear the computer. And here are some symptoms, when coming to a stop, you can feel a very slight vibration or stumble, but the tach or speedo doesn't show any of it, it goes down smooth. Also, does anyomre know where the PCV hose is on a Lightning.....

 

I have a 2003 HD and the same problem (code 171) happened to me with only 35 miles on the truck. I checked hoses and connectors and found the PCV valve wasn't hooked up (not pushed into the valve cover). Too much pressure may have popped it out, I don't know?

So you may have that problem too, check your PCV on the pass side valve cover.

Sean

 

What about the o2 sensors? Do they need to be replaced?

 

if you upgraded to the 90mm, your chip has to be programmed for it. If you don't have a chip, i'm surprised that you weren't having trouble much earlier. If you don't have a chip and upgraded to the 90mm, you have to have a chip programmed for it.

When ever i send my chip for a reburn, i carefully drive my truck. But if i go over about 2200rpm, the ses goes off and i get that same code.

 

I have a diablo chip dyno tuned from Paul at Razors Edge Motorsports, and that was a coulpe weeks prior to the SES light. And yes, he knew about the 90mm mass air. And will the O2 sensors trigger these lean codes...

And i went and looked at my pass side valve cover, and i saw the one hose that connects into the valve cover. I check it and all the hoses around it, i don't think there's a vacuum leak. How can you tell, a couple hoses have very thick padding around them...

 

Did you just put a full header and cat back exhaust on that truck?

 

No, I've had a Borla catback for almost a year now.....

 

You've checked for the PCV tubes in and tight. Did you check the tube that is pressed into the left camcover--it connects to the bottom of the intake boot. Also, be sure your IAT sensor is pressed into the air filter box.--and connected.

Dan

 

With what you describe as a slight stumble at idle tends to make me look towards the PCV hose and connectors (or some other vacuum leak). The elbow in back of the manifold is impossible to see, but if you leave the engine running and place your hand at the end of the hose going into the manifold you will feel it suck your finger in if it is cracked and has a leak. I had checked mine twice, but the day before it was to go into the shop, I tried one more time and was able to feel the leak with my finger. I replaced mine with a new PCV hose and valve for about $16.00 (it came complete with the valve, hose and the elbow), but I have heard others use a boot off of a sparkplug, as the end going into the manifold is bigger than the hose going to the PCV valve. If you do a search under engines you will find other information regarding these codes. It's unlikely, but not impossible that the o2 sensors are bad. Many people jumped to that conclusion, only to replace them to no avail.

 

Could someone tell me exaclty where this elbow in the back of the manifold is, or something. I really want to find out whats wrng eith this thing. Lightningrod, i went out and checked the one that connects to the boot, its in nice and tight.