Hi, this is Danny.
I have a '94 altima w/automatic transmission and Iam also having a poor
millage problem and the O/D light flshes when I turn ignition switch to
on. Somtimes when I turn the car on the O/D light flashes and the car
shakes/shivers.  I first thought it was MAF sensor problem but whem I
retreive the DTC's only code 02, Vehicle Speed Sensor (vss) circuit
problem appeared. I tested the vss for continuity and for AC volts it
tested ok. I checked spark plugs, replaced air and fuel filters, changed
motor and tranny oils and tire pressure is good. The good thing is that is
does not die on me.
I don't know what else to do to. Any suggestions? Please.

Thanks in advance
Danny from Fresno, Ca