hello i have a question on my 1986 mercedes 300e it falls dead 5 minutes after the first start in the morning. it starts up great but when it fall dead it wont start untill the next day. ok... here is what i dont understand about this car. on the first start if i hold the accelerator to about 2000 rpm for a few minutes it wont fall dead. i change the fuel pump,fuel pump relay,fuel filter,i check the fuel pressure regulator. when it fell dead i disconnect the fuel line from the fpr turn it over and fuel was coming out good. i dont know what to check next do anyone know what i should check for next im lost thank you for the help guys.

I have a feeling you're going to need to get a fuel pressure gauge to figure this out...It definitely sounds fuel pressure related.

Once you have the gauges, we can see what is going on. Pressure might be dropping off causing the car to stall.
Do the standard vacuum leak check at the idle air hoses and check for leaking fuel at the fuel distributor to airflow unit, and between distributor and eha.

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Fuel system pressure must be 85psi for that car, you most likely will need a guage (as suggested) to find the problem.

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ok.. thanks for the reply i will try that soon.