Hi --

I live in Massachusetts and my 97 Nissan Altima failed the state
emissions test  -- the check engine light was on (had been for 1.5
years without any problems) -- I went to a state-registered auto shop.
They performed the OBD -- that gave 2 codes.  One for a knock sensor
and the 2nd for a crankshaft position sensor.  They replaced both
sensors.  When they did the repair, the electrical system had to be
reset.  I had driven the car over 200 miles and still one system
needed to be initiated.  At that time, a new code appeared, again
indicating that the knock sensor was a problem.   I drove the car
another 200 miles and I have taken it back to the auto shop and the
electical system is still not "Ready."  By the way, the check engine
light has not come back on.  

1. Is there anything I can do to get the car "Ready"?
2. Is there something else wrong with my car?

Please help!  Thanks.