Can your pickups be too high? i raised my bridge pickup so that it is just low enough not to get hit by the strings. Can it ruin your tone if you get it too high?
Gibson SG Standard
Ibanez S2170FB
Peavey JSX
Marshall 1960A
Yeah , but it all depends on your ear. It can mess with sustain and stuff.

The Gear I Use Most:
Gibson guitars, Les Paul, ES-335, SG and more.
Dunlop Crybaby | Dunlop Volume | Boss TU-2 | Ibanez TS-9 | Maxon AD-999
Planet Waves Custom Leads
Marshall JCM900 (model: 4100 + 4101)

TooJoo The Band
It does depend on what kind of magnet's in them. Alnico's a weaker magnet than ceramic so they can be closer to the strings. If it's too high the strings will lose sustain due to magnetic pull, but if it's too far the pickups won't receive as much vibration. Just experiment and try to find a balance.
Id suggest everyone play around with their pickups heights. It makes a huuge difference in the tone and response of your instrument. You can hear it easily adjusting then playing ect ect