What about multiple codes?

Question

My daughter is looking at this car - the MIL is on, and I'm getting a P0171 - System Too Lean Bank 1, and Cylinder 1 through 6 misfires.  We know the exhaust system is bad from the final catalytic convertor back.  Is it possible that all the above codes are related to the exhaust system, or could we be looking at a serious problem in the making?

Answer 1

P0171 Fuel trim lean Bank 1

This is the condition of the engine, what happened is the front or upstream 02 sensor is what is setting this code, this is in front of the catalytic convertor. A faulty 02 sensor can set this code, a vacuum leak can set this code low ,fuel pressure or  a engine that has coolant seeping into the combustion chamber can set this code. Until the lean code condition is inspected and its cause is found you may just be looking a  bigger problem