So test drive on six new plugs, six old.

Misfire at about 85 mph in 4th gear. Also 500 code and 503 wheel speed sensor.

Who can tell me about this code?

I did just replace the steering knuckle, but I used the old speed sensor when I did it.

Is it possible that I damaged it somehow in the removal? Will this cause misfires at high rpms?

Thanks again for taking a look at this with me.