Speedometer / Odometer flakiness

Hi folks,

Took my '87 Testarossa for a jaunt up to Germany, and as I was stretching its legs at around 240kph the speedo did a couple of back-and-forth sweeps and then conked out. The odometer also stopped registering, so at the next rest stop I pulled in, turned the car off, gave it a few minutes, and when I turned it back on it was happy again.
Reading a couple of (OLD - https://www.ferrarichat.com/forum/threads/tr-speedometer-died.66295/#post-135057824 , https://www.ferrarichat.com/forum/threads/testarossa-speedo.29084/) threads here, it seems like this could be a sign of the sending unit being on its way out ? It did it once again afterwards, but this time it "fixed" itself within a few seconds, and that was it, nothing else for the rest of the drive.

Wondering if it might also have to do with the high speed run, since both times this happened it was north of 200kph, which I don't think it saw very often until recently.

Has anyone else experienced this ?

Greetings from near the Nürburgring

 

Thanks, both! The previous owners hadn't cracked 30,000 km on it when I bought it earlier this year, and I've since added a couple of thousand already, so it's seen more driving in two months than usual. I assumed this would highlight anything that's on its last legs, but so far the only thing that has complained was the speedo/odometer, and it seems this could also just be due to operating at the extremes of its range.

 

Alright, so I definitely think the odometer/speedometer flakiness comes from the temperature -- was cruising mostly above 200kph today for about an hour, and at some point it just gently started dropping down until it hit zero. After about 15-20 minutes of driving at a much more relaxed pace, it recovered again.

Anything else that comes to mind, David ?

 

Right, sorry, should have been clearer, that's what I meant, that the sensor overheats and stops working correctly.