1998 Vauxhall Zafira 6 cyl Two Wheel Drive Manual 82,000 miles
When I have been travelling about 60 miles at a steady speed on the motorway, the car will begin to lose power.
If I release the gear and coast a bit then re engage the gear it will return to proper power. If I stop it will not lose power again for about 20 miles but then it will do it every mile or so. I can drive miles on ordinary roads and this doesn't happen.