I recently purchased my second disco and it drove great when I drove it home and on a 300 mile trip from Seattle to Idaho. Had it around Idaho for a few weeks then on the way back about 270 miles in it started to have a weird surging acceleration when cruising.

It idles fine even after a long drive or cold start, but when cruising at any speed it surges as if i was on and off the gas slightly.
based on experience with my last disco Im assuming its the throttle position sensor but it could be the VSS even though there is no misfire and the only check engine code is for an O2 sensor heater.

mainly wondering if anyone else has dealt with this or has any more ideas?