JRV

Hi Mark,

there is only an idle mixture (AF) adjustment for the system not any type off idle adjustment. Off idle mixture is controlled via Aux. Control Pressure Reg. and the Frequency Valve using Open Loop controlled by the Throttle Position Sensor (and coolant temp sensor when cold, in open loop) thru the Lamda Computer..

The dirty/worn injector theory put forth is a definate possibility and the other check you could do is Fuel System Pressure.

It wouldn't hurt to know exactly what system pressure your particular ACPR is keeping that system at. If the ACPR is getting tired or is out of spec this would be hard to detect with an ass dyno, but readily picked up with a chassis dyno.

Then there is always the art of fine tuning which takes the basic specs good enough for Gov. work and dials them in to a more real world book spec perfect.

Regards, JRV