Well, pulled the fuel pump relay opened it up and there were no signs of cold solder joints or cracks around the pin mounts. Put it back together, stuck it back in and now the car does not stall anymore. My guess is the relay just needed resetting. Only thing I need to adjust now is a fast idle. Mysteriously enough several gremlins cleared themselves up as well. Speedo and tac now work correctly and cruise control works again.

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89 190E
2.6L
Arctic white
Grey leather
Sunroof
Pirelli P400 rubber
Smoked corners