'02, F350, V10. I had a P0171 and P0301 codes as read by Auto Zone. I had planned on changing the plugs anyway since I didn't know the history of the truck.

So I changed the plugs and boots - what a PIA job that is! Anyway, how do I reset the check engine light, just disconnect the battery?

Thanks.

 

Yup, just disconnect the battery for an hour or so.

The "bank 1 too lean code", P0171, can mean a vacuum leak. That pesky rubber elbow for the PCV plumbing as it hits the throttle body can do that to you.

The P0301 is a cylinder #1 misfire, is in "bank 1", and again, that vacuum leak can cause that too.

I don't think the plugs are what is causing this, and a few drive cycles will clear that light even without disconnecting the battery. So if the codes are still there, it's still doing it.

 

Thanks. The check engine light came on sometime after I replaced the gas cap due to a failed emissions test.

I read here that poorly sealing caps can cause the light to come on, so I put another new cap on as well. I'll check the PCV hoses too.

 

or anybody else. The PCV line has some sort of insulating rubber foam hose over it. At least I'm assuming that that's not the actual PCV line. The foam is crumbling and disengrating. What's the purpose of the foam? Do I need it? Per Krewat's suggestions below, I want to replace the PCV elbows and hose. Can I get the PCV replacement elbows at Autozone, or can I just eliminate them and use a single hose to the PCV valve?

Thanks!