280e won't idle when warm
 

Hi, new to the forum. I have an 84' 280e euro that won't idle above 80c. It starts and idles between 700 and 900rpm, as the temp reaches 80c the idle slows down to nothing. Recently but only once or twice it has been hard to start. Like it was out of gas maybe. I also believe I've been experiencing a loss of power for some time. I replaced the fuel filter and ran two bottles of injector cleaner through, no help.

I suspect the fuel pump. Is there a simple test to correctly diagnos the problem. The pump is costly so I don't want to replace for naught. Also i don't have a fuel pressure tester. Where would be a good place to get one, and what type, manufacturer, cost, should i be looking for.

The car has approx. 160,000 miles and is a daily driver. It is a factory ralley car that has been converted. The roll cage was removed and an interior installed.

Thank you for any help.