spark dies on 300e

[derk4316]

its an 87 300e has been at the mechanics for months all tests turn up that everything is fine but once the car is driven for about 30 minutes it dies. and there is no spark at all
have replaced
crank sensor
ignition control module
coil twice
all relays with brand new ones
checked every wire we can think of
still cant seem to locate the problem the last thing i can think of is to put in a new computer. any insight from anyone would help (coulda sworn it was the coil or crank sensor but the new ones i put in test good)