I'm getting no power to the fuel pump, except when key is fully engaged (starter motor running). When key returns to operating position, fuel pump dies.

This is an intermittent problem. First time truck died (like it ran out of gas, but I had 1/4 tank)going up a slight incline, towing 4 horse stock trailer. Banged the in line fuel filter, worked the throttle cable manually, and she restarted and ran. Made mental note to replace fuel filter.

Before I got a chance to swap the filter, it died for want of fuel again, on a slight incline. Could not get it started, bang on the filter did not help. Friend passed by and pronounced it to be a bad fuel pump. Had it towed home, took the filter off, it was full of rust specks. Changed the filter, truck started and ran great... for another couple days.

Third time, died on the downward incline (very slight). I noticed I could restart it reliably, but as soon as ignition switch went to operating position, fuel cut out. As long as the starter motor was engaged, fuel pump operated just fine.

Had it towed to the shop. Given the above description, they opted to glue the plastic 4 port vacuum thingie back together. It's been broken for all two years I've had the truck, but it started and ran for them, I think they didn't know what else to do.

Ran for a couple days, was just starting to figure it must have been a vacuum leak problem after all...

4th time it died at a stop sign on a slightly steep uphill, one light from home. Ran it with the starter motor engaged, got through the corner, pointing downhill to my allotted street parking space.. whew! Too cold to walk home.

Now, I just don't know what to tackle first. Ignition switch? Is there a fuel pump relay that could be bad? Fuel pump itself?

Other than being fairly certain I've got an electrical problem, haven't got it pinned down.

I need a diagnostic protocol which goes from easiest/cheapest to hardest/most expensive.

oh, and I banged on the bottom of the tank, in the middle, where I thought the pump might be. It made a little gurgle, which I thought promising, but still no fuel. I have dual tanks, and only the rear is in use. Front tank had fuel door taped shut when I bought the truck. Let sleeping dogs lie for two years, but flipped the tank switch momentarily the first time truck died. I think that's where the rusty specks in the filter came from. It's had clean fuel running both in and out ever since I changed filter.

Already blew 5 times the cost of new pump on getting vacuum leaks reduced, hope I can afford this one, and hope I am mechanic enough to gitterdone!