1999 merc efi 454ci w/m3 pro charger, need help finding info on the pfm super prom, engine starts breaking done above 3800 rpm . there was a stricker on the engine "woffeis marine". fuel psi 65 at 3800, if you try to give it more thorttle engine sound like it is detanating. any thoughts would be helpful.

check out the sparkplug gaps, you could be blowig out the spark with the procharger's boost if the gap's are too big.

check gap .035 per merc, checked with pro charger tech support they rec. the same. they did not know anythe about the pfm super prom tied in to the system.

Dist cap and rotor replaced?

If they all look good then check the heat range,,did someone put chitty fuel in it?

fuel is good , but also ran it on the shop tank, cant find any info on the pfm super prom piggy backed in to the harness.
changed all filters, and full tune up (cap rotor plugs wires)
comp 140-150psi all cylnders running aromotive a1000 pump, and boost psi reg fuel psi should peck at 70 at 4900.
I concerned about the pfm super prom piggy back in ,it has 2 knobs that read high and low. Can not find anything about this product. need help

to my knowledge that piggy back isn't available any more or supported. My last use of it was in 2000 andassistance then was limited.

Since it's a 99 do you have a MEFI 3 ECU? I support tuning all MEFI units and may have a base tune that could be installed onto the ECU allowing you to completely eliminate the piggy back.

http://www.mefituning.com