I was just thinking, I have been getting the DTC codes for banks 1 and 2 lean and was wondering something. If this code is due to an exhaust leak before the O2 sensors than the computer may just think its running lean and be unneccesarily adding fuel which means I could actually be running pig rich as a result. However if it is due to getting unmetered air into the intake manifold than I could actually be running lean so would there be a way to know if you are actually running lean besides looking at the spark plugs and checking for color? I dont have any kind of scan software other than my interceptor guages which can read LTFT, STFT, O2 voltage etc.

 

Make sure the wires on your mass air meter are clean. If the're dirty clean them with electrical contact cleaner and make sure it is dry before hooking it back up.

 

You should be able to hear an exhaust leak like that. If the plugs are black and fluffy it's running pig rich, if they are ashen or glazed it's probably really lean. Usually unless you have really crappy exhaust you'll not have both banks setting codes at the same time. Codes on both banks, without a large intake leak, usually point to a leak between the MAF and throttle (including an open PCV system).

Vernon

 

Yea, my header bolts keep trying to back out on me, the passenger side has a slight burn mark on the side of the heads where exhaust was getting by the header gaskets, its those crappy pacesetter gaskets, so Im switching those out for stock gaskets but dont know if that was enough to cause lean codes. I sprayed the hell out of the intake tubing and manifold with carb cleaner while it was running and cold and no change in idle. If I cant find any exhaust or intake leaks, Ill probably try a new tune since I need one anyways and if dont work Ill look at the MAF sensor and fueling.

 

Depending on how long it has been doing this(throwing codes) If you have cats still on your truck, there is a good chance you have cooked them.

 

Cats went bye bye and tuned out when I got the Pacesetters.