I have an '89 formula and this summer when I first got the car it ran consitantly 16.2 @ 83mph, bone stock! Over the past couple of months the only thing I did was change the fuel pump. I took my bird to the track yesterday and It ran 17.1 @ 80mph twice!?!
The only problems I can tink of is that somehow Im not getting enough fuel. Either I think pinched one of my 4 rubber fuel lines comming from my sending unit, my fuel filter is dirty, or the fuel line, included, to replace my factory pulsator it the tank is too skinny and restrictive. All 3 of these things could be causing restricktion, what could be the most brobable cause???

 

Did you check the fuel pressure before and after the pump change? Maybe the better pump caused an increase in the fuel pressure which now makes it run rich at WOT