Sounds like you're fuel starved. Like LPB says..clogged fuel filter. Or fuel pump on its last leg?
Does the engine catch up after you drop the revs back below 4000?
Josh
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.