Those codes are for an oxygen sensors-might be on the lean condition and not switching and computer throwing fuel at it due to its reading lean.
Starting problem could be the caused by a coolant temperature sensor not telling the computer to enrich fuel demand during cold starts before the oxygen sensor goes into closed loop to control fuel mix and also low fuel pressure.
Poor gas mileage can be anything within the vehicle sub-systems.
When the last time it was tuned-up? Maybe you should consider getting it tune.
Wednesday, October 28th, 2009 AT 8:05 PM