Stumbling on Highway

[RemCharger]

Update: I bypassed the mechanical pump and started running just the electric pump with a regulator set at 6psi. It doesn't stumble or die anymore on the highway. That tells me the mechanical pump is too weak to keep up. Guess I need to relocate the pump to the rear of the car though. It's pretty noisy being right under the front of the trunk pan.

It could also be telling you that a mechanical pump is not designed to draw through a non activated electric pump.
Try bypassing the electric pump, THAT will tell you if your mechanical is weak.

 

[nutz4spd]

I may do that just to see what happens. Thanks for the suggestion.

 

[Geoff 2]

Re-read post #10.