Generic PID controller

[Ric Rainbolt]

>I need a generic PID controller which is required to control fuel rail
>pressure via a PWM modulated pressure regulator (about 2-3A at 100%).
>The input is a 0-5V ratiometric pressure sensor.  It is mobile therefore
>needs to be powered by the standard 12V auto electrical system.  The
>main requirements (apart from the above) are:

Tell me more about this PWM controlled pressure regulator.  I  need this for
a non-automotive project.  How much and where can I get one?

Thanks,
Ric Rainbolt