I do not have jackstand to support car and get underneath. Can I reach the oxygen sensor from the hood of the car? I did that in smaller cars like mazda protege but this one is a lot different.
Can I change o2 sensor on 1999 crown vic without going underneath the car?
You should be able to get to the upstream O2 sensor. The downstream is behind the Catalytic converter so you will probably have to go under the car. Unless you are very skinny and can slide under the car get some jackstands.
Can I change o2 sensor on 1999 crown vic without going underneath the car?
No
