Brian. sorry I am no good on writing. You need the MULTIMETER with duty cycle. The rich/lean screw in the filter housing only adj idle rich/lean.The EHA screw adj off idle. You need that adj to 30% to 40% at 2000 RPM. Air flow meter test is for how many air go in to engine. At idle if over .9v. When idle down the RPM will down to 4-500 rpm then go back up or stay there or stall. Check the air flow meter volt first. The EHA is for fine tune the engine. All so you need check the KLIMA RELAY .The one beside the fuel pump relay. This relay control the idleing, Open the couver check inside see is any solder is crack. If you need to adj the air flow meter volt. Pop both side small couver out at air flow meter. You will see 2 screw each side. Loose it about 1/4 to 1/2 turn. tap the meter back & fore to adj to .65v to .85v. And check the fuel pump and OVP relay. Hope this help. Let me know.