G35 Speed Sensor rubbing

[marcInDallas]

2003 G35 with 72,000 miles. Purchased used in December of 2006.

I searched the posts and did not find anything.

Symptoms: ABS, SLIP, and Service Engine Soon lights are on. From time to time the lights will go off as if everything is fine but then my brakes go to cr!p(reverse of wheel hop feeling). This will last a few stops and the lights will come back on and everythnig is fine(that is, the car is drivable).

Had it checked and it was deterimed that it was from the speed sensor. That's what the mechanic told me. Might have been a code reading or something more general to lead him to believe it was the speed sensor. Funny thing is, when the speed sensor was taken off, a washer was between the speed sensor and the mounting location. The mechanic does not have an Infiniti background(Lexus) but thought it looked non-factory. Without the washer the speed sensor rubs against the metal(?) piece it picks up rotations from when I turn the rotor. With the washer on, it has enough clearance but does not seem to be right(maybe too far away).

I do know the car has mods(lowered 2 inches, pedals).

When I bought the car the guy told me that I would need to replace the drivers side speed sensor. Didn't think the guy would steer me wrong due to him being a member on various G35 forums with many posts. Oh well, got a good deal on the car(time will tell). Just for clarification, by no means am I saying the guy is a liar.

Question: Should there be a washer between the speed sensor and mounting location? If not, should the speed sensor rub?

If there should not be a washer is there any thoughts as to what could have been modified in this car to create the rub?

I noticed the device the speed sensor "picks up from" is removable. Thoughts on if this could be a factor.

Thanks,Marc