1989 Ford 460 E 350 not running, need help

RVKamper wrote:
You are all great, thank you for the input. To expand on the second paragraph as someone suggested, it is when I rev the motor in neutral that it settles. And other than the rattle that settles, it seems “normal”. As far as the behavior when driving, it slowly, gradually loses power until I’m creeping along in the shoulder, then the tow truck. My thinking tells me if it was a catastrophic failure in the engine, as was my first thought, then it wouldn’t run at all. My home made other demands on my time this weekend (can you say garbage disposal?), so I have not gotten under the rig yet.

If I understand your post correctly, it starts fine runs fine for a while then gradually loses power until the engine dies? How long does it run fine for at hiway speeds? Hours or just until engine comes up to temperature? When was the last time the in tank fuel pump was replaced? How many miles ago?