Why did the pump fail, could it be rubbish or water picked up in the tank ?
did a change of Fuel brand cause the buildup of deposits inside the fuel lines and tank to let go and circulate ? This would cause a drop in power as the fuel filters start to clog up. But I am not sure if this would lead to over heating unless the timing was being over compensated .
Start fault finding with the most simple things first, ie the fuses.
Cheers Arthur

