grey wolf
Newbie
Just going to throw this out there, but if you have a misfire you could still be getting a lean reading. Remember the O2 sensor shows oxygen content in the exhaust stream, therefore unburned oxygen from a misfire would cause the O2 sensor to give a lean reading. Also, do you have an EGR system on your engine still? Might be a stuck open EGR valve or something like that. You could try sticking something under the EGR valve (like a business card or piece of cardboard) to block the flow, see what that does.
