928 Low Voltage and Low Power HELP

[vintageair]

hi guys-
i am having major electrical problems with my '81 Euro 928S.

When i am full throttle, my acceleration begins to cut-out after 4500rpm's. I could not figure out why, then my "mechanic" looked at the coil, and noticed that the voltage was only 9.5.

he checked the 12v wire that attached to the "tap" located near the front passenger's side of the engine compartment for jump starts, etc. it was putting out 12v. he then ran a test lead directly from the 12v source and connected it to my coil. i then drove it around the block a few times and noticed all of my problems were fixed in the short term. i was able to hit the redline with no hesitation.

what should i do now? what is the reason for the loss in voltage at the coil? can i wire it and rig it to fix this problem? it there a way to correct this without doing a cheezy wiring job?

please help!

thanks in advance,
josh

[Ebs]

Are you sure that's the issue?

I once had a smiliar problem, and that was because in the car (albeit a Mazda) the factory fuel pump wasn't powerful enough. An electric higher pressure unit fixed the problem. Just a though...