1996 Contour Fuel mixture too lean

[stasea]

the check engine light is on once again, the code read fuel mixture too lean. This happened one year ago, and the mass air flow sensor, coil pack, plugs and wires have all been replaced. Has anyone had similar problems? We are wondering about replacing the O2 sensor and/or the air intake tempurature sensor (the problem seems to re-occur during colder tempuratures) . The plugs are fouled out so they will have be replaced again, before we replace these two sensors we just wanted to see if there were any other ideas?

[goon]

make sure the throotle body is clean and the temp gage is working, and the engine is running at the right temp. and no vacuum leaks.