1980 242 missing under hard aceleration.

I can hear the main fuel pump surging, randomly cycling off and on every couple of seconds)
Strange thing is this problem only starts once the car reaches operating temperature and not when cold.

What I’ve done so far:
*replaced both fuel pumps (Bosch)
* Replaced accumulator
* Replaced fuel filter
*Replace fuel injectors and rubber O-ring seals
*Disassembled and cleaned out intake system
*Soldered new clip-on terminal wire spades behind main pump fuse #8.
(#8 fuse ran very hot prior to this fix)

I’m thinking I should locate and check both ends of the main fule pump wire but have no idea where they terminate to?

The fact that this fuel pump surging problem dors not happen when cold is perhaps a clue someone can help me with?

Thank you