91 mercedes e300 won't start when hot

when the temperature is above roughly 60 degrees, I can drive the car for a short while, even a few miles, and it will start to sputter and eventually stall. At that point the car won’t start, it turns over fine, but sounds like it’s not getting any gas. If I wait 15-20 minutes it starts fine and will repeat the same process. Is there some temperature sensor or something that prevents the engine from starting after it gets hot, or is it something else. The temperature gauge doesn’t indicate the engine is hotter than normal. I’ve taken it to my car shop twice and they haven’t found anything.

You may very well have 2 coolant temperature sensors (one for the gauge and one for the PCM)

A bad ECT sensor will definitely cause problems.

Here are some other culprits, based on my experience:

Fuel pressure accumulator
Fuel pumps (you might actually have 2, they are external, by the way)
Fuel pressure regulator

Are you fairly certain you have sufficient fuel?
The fuel gauge in your car is not known for being terribly accurate, especially when you get down to 1/4 or less. Ditto for the fuel sender.

I don’t think fuel is the problem. The repair shop thought t might be bad fuel and replaced and made sure the tank was full and put in an additive to stabilize the fuel. It’s done this over a number of fill ups. But I agree with you on the fuel gauge, sometime it’s flakey and reads full for a while when I know it’s not. Then it returns to working normally.

Bad fuel could be the problem if the vehicle has sat for months or years.

Have a mechanic test the fuel gauge and the fuel sender separately.

85 ohms full
2 ohms empty