Temp gauge drops to 0 when cae is driving over 2000 rpm

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. Which engine is your F250 equipped with? This is a very important question. Assuming that you mention "vapor locking" leads to gasoline engine - like the 6.8L V10 or a 5.4L 3V V8. Any warning lights on? Drivability concerns lead to fuel, spark and air mixture concerns,, and exhaust flow questions. If exhaust is restricted, you will lose power. If air intake is restricted - same thing. Hands on testing is needed to find out what is choking your engine. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.