my 87 420 sel has a problem that i would like to fix, on a "cold" start in the morning (i live in central florida, it averages 70-80 deg. in the morning) it almost always starts right up and idles smooth. but if i drive it to full operating temp. and try to restart, it cranks as though it has lost fuel pressure, i want to put in a couple check valves in the fuel pumps and an accumulator, but thought maybe i should ask the experts here. i feel that it probably couldnt be injector related as it starts and holds pressure sometimes as long as a week between "cold" starts. i have tried to cycle the fuel pump many times by turning the key on/off and letting the pressure build before a warm start and this doesnt seem to work. when it does this cranking over many times routine it seems as though it is flooded and smokes black and smells like gas when it starts(making me think injector problem) but the only catch to it is, if you pump the gas, it will start sooner(ie:starving condition), if you hold the throttle open(ie:flooded condition)it wont?!!?! the plugs look fine, a little rich maybe but i live in the city so they are about as they should be. i dont have the pressure gauge to check the system and really dont want to start throwing parts at it, any suggestions? also once the car is running, it is smooth and has no issues, only the warm start issue. does it seem reasonable to change the check valves and the accumulator and go from there?
p.s. had recent tune up and fuel filter

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2003 audi A6
2002 porsche boxter
1989 jeep grand wagoneer
1987 m/b 420 sel
1966 vw type 1
1965 mustang "a" code gt