I got a wiring schemtic from ford and wire it up like the schematic.

FIXED. Someone had changed wiring harness to A/C compressor. Power wire from heater control feed directly to compressor clutch. Signal wire to pcm was tied directly to this wire. This caused pcm to shut down when A/C clutch cycled.

YES. Engine dies only when A/C cycles "off" and when horn honks. When horn is grounded to honk. Engine dies.

Still acting up. Cuts out when A/C cycles, honk horn. GEM failure? HELP

Checked all grounds, power connections, fusible links, central fuse box, reference voltage to cam sensor, crank sensor, ICP sensor. OK. No lose of voltage to sensors when A/c or horn cycles. Replaced fusible link between battery and alterntor. Was ok for a day. Alternator has bad diodes. Alternator ...

Engine dies when you honk the horn and when A/C cycles. Always restarts. Codes P0603, P0344, P0677. Cam sensor was replaced recently. Intermittent glow plug code. KAM error. Battery was low.

I have to wonder if this is not caused by the removal of zinc/phospate in the newer oils

Thanks for the help. TSB under 2005 model year. Drive gear was redesigned.

Oil pump drive assemble making noise. Drive gear on bottom worn. Bushings in assemble rinning with little or no lubrication. Replaced oil pump drive assemble. Cause of lack of lubrication. Car has 25000 miles.