I've got a 1990 ford ranger, with 2.9 liter EFI package.
About three years ago, I had to replace the O2 sensor after, well, it 'died'. Symptoms had been loss of power, bucking at highway speeds (on a flat stretch, having to down shift to maintain speed), and loss of gas mileage.
Now I've got a sixty mile commute, and there seems to be one stretch on the way up in the after noon (I work nights) where I seem to have to shift down (fifth to fourth) to 'clear' the bucking, and then I can shift back up to 5th. So I'm suspecting the O2 sensor (again) but does anyone have any idea how long those are suppose to last. Its been about 3 years and 50,00 miles if that is any help.
thanks in advance for any help.
peter