Though the Ford EEC-IV mass-air SEFI system is very adaptable, in stock form it cannot make the substantial changes necessary to provide the optimum air/fuel ratio for a 400hp engine such as ours.

Ford EEC one-dimensional parameters are typically referred to as "scalars." These are things like engine cid, idle speeds, injector sizes, rev limits, and so on; a small sampling shown here.

While the Ford EEC-IV and EEC-V fuel-injection systems are reliable and feature easily-sourced hardware, the performance tuning of the system leaves something to be desired.

The 1986-1993 Ford Mustang's EEC-IV has the capability to manually test for codes. Not just that, but you can also check the Continuous Memory codes that are stored in the system.

The Sequential Electronic Fuel Injection (SEFI) system and its EEC-IV controller would become standard on the 1986 Ford Mustang GT and all 5.0-liter Mustangs through the 1995 model year. Though Bieber ...