Lowest O2 Sensor on 00 XJ - Ok to disconnect?

2000 XJ Sport 4.0L auto.

50% of the time it won't idle. Idle drops to 200 or so, then stalls.
If I compression brake for a bit to build vacuum, it usually will idle afterwards.

The wires going to the lowest of the 3 O2 sensors got melted together near my thermostat housing. I *think* this may be causing my EGR to remain open all the time.

If I were to cut the wires for that O2 sensor (right where they come out of the harness near the front of the fuel rail), would it have a negative effect on drivability?

Any other suggestions welcome also. :dunno:

Also... would an open EGR give me a whistling sound (similar to a cheapo TB spacer) when opening the throttle 'moderately aggressively'?

Only mods are a Flowmaster and a K&N FIPK, both have been installed for almost a year w/o problems.

Don't cut the O2 sensor wires as you would have definite driveability issues & your 2000 model year is supposed to be OBDII Emissions Standards compliant & would be considerred tampering by the U. S. Department of Ecology if you disabled just that O2 sensor. Cutting the wires will also likely cause your check engine light to come on & stay on, if it hasn't already. Instead what you should do is talk to one of your Professional Mechanic friends about repairs to that segment of your wiring harness as he or she might be able to cut you a deal. Also, in order to prevent such a wiring melt-down from happenig in the future, you should make sure that your wiring is routed away from hot engine components as much as possible. Does this help?