So I was on my way back from picking up an engine today and my check engine light pops on. Drive for two hours back home and only thing I notice is the truck idling rougher than normal...like it had a major vacuum leak, but not quite as bad as a misfire. Pulled the codes and came up with a bank 2 lean code, as well as both knock sensors low input. I put new knock sensors in the truck about 400 miles ago and have had no issues until now. I went through and sprayed the passenger side of the intake with brakleen and couldn't find anything, also sprayed the pcv line and still nothing. Also the truck will only idle like it has a vacuum leak from time to time, at one light it will be normal, the next chopping hard and acting like it wants to die. Any ideas?

 

what are the codes...

 

Its pulling a PO174, PO327, and PO332 code. Both knock sensors and the intake gaskets are brand new. I'm assuming though that the knock sensor codes are due to the truck leaning out on the highway though.

 

And you sure you dont have a vacuum leak? can't you spray throttle body cleaner around the manifold and hear if it revs up?

 

Change the front o2 sensor on that bank.

Dirty

 

I sprayed some brakleen all around the intake and couldn't find anything. So either it's leaking on the inside edge where I can't spray, or I'm just missing it. Also both front 02's are new as of about three months ago, so I don't think they should be the issue.

 

swap em bet the code changes from bank 2 to bank 1

 

I'll try it. The question then is what triggered the knock codes?

 

Mine did that awhile back...it was just bad gas

 

Lean missfire form the bad o2

You did new o2's when you put a new set of headders on ... Right? The **** burning off inside the new headders has a tendency to kill o2's. they live for a while but dosnt take long for them to give up.

A good vacuume leak would rock both banks as would a clogged fuel filter or bad pump.