Yes, I do have a slight exhaust leak on cold start up. Funny you mention that,...I was just eyeing the manifold bolts about an hour ago wondering if I could tighten them a bit without risk of cracking or breaking anything.

Why do you ask about the leak.........can that throw the lean code?

Brian

 

No you cannot tighten the bolts, it is a crack in the exhaust manifold itself. VERY common on LR's, once the manifold heats up and expands then the crack goes away. A muffler shop can weld it, other than a new manifold that is the only other fix. And no it will not thow a code because of the leak. Unless it is REALLY bad.

 

if its only a small leak, i doubt its your problem, but yeah, a exhaust leak will suck air into where it leaks out inbetween exhaust strokes, when it does, itll trick the o2 sensor into thinking its running lean.... anyway, you need to find out if you have a vac leak, generally a mafs will throw both banks, since all the air goes through it for the whole engine. could just be a o2 sensor, check your air filter cover, make sure its on correct, not bent in on the back lh side at the filter (looking at it)