On the bottom of the intake there is a box that has cables on it that lead to the IMRC's when the RPM's hit 3250 the ECM tells the box to open the butterflies up. This is Ford's way of fixing the Low end torque on the early 4V's. I'm not sure if the new heads on 99 up fixed the problem or if they did something else.

 

yeh i got a 98 cobra with 150,000 and had the IMRC butterflies replaced... i had no idea u could delete them godddamanit

 

Ouch how much did you get overcharged for that.