Noise and gas problem

I have a 1994 Altima with two problems. The first is a noise. Shortly after engine temperature is obtained, a "chirping" soung occurs during accereration. It stops after higher RPM's, but is quite loud up to that point. The noise appears to come from the engine compartment. This may be a common problem for these cars for recently I heard the same noise in another Altima. What could this noise be?

The other problem is a tremendous drop in gas mileage. A tankfull of gas does not get me more than 140 miles! This is a recent occurance. Any ideas here?

Carl

The chirping might be related to one of the rotating pulley like the power steering pump, alternator, etc.

The low gas mileage problems is possibly because the engine is stuck in open loop mode. Two things comes to mind, the O2 sensor and the engine coolant temperature sensor.

Check the ECU for diagnostic codes.