M117 4.5 Hard Hor Starting — 15–20 Minute Rest Period

I'm experiencing an issue with my car that's puzzling me. When the engine runs fine but then sits for 15–20 minutes before restarting, the car becomes very difficult to start. After several attempts, it usually fires and runs normally.However, cold starts and restarts after 30–45+ minutes of running both work without issue.Recent work completed:

• Ignition components replaced
• Injector trigger points serviced
• Throttle position switch (TPS) replaced

I'm trying to narrow down whether this could be vapor lock, a leaky injector, or something else entirely. Any insights would be appreciated.

W108 1972 4.5 USA

...check if the hotstart-device is working !