[RyanAK]

Thanks guys.

Wikid61 - fuel filter was the first thing I wanted to replace. Looked rough, but it seemed as though flow was still ok. Of course the parts store didn't have a filter in stock, so I had to wait to do this part. Then the wrong filters came in. So more waiting.

I wouldn't say this was happening on steep grades... just long ones. Felt like running out of fuel... or that the fuel system couldn't keep up on a prolonged pull up the hill. 3rd gear, 70 mph, dragging a heavy Suburban up the grade. No load other than the weight of the truck. It was also the first really warm day of the year. No rise in engine temp.

Hoses... I checked at the tank after I got towed and all seemed good. Then there's a short section of hose between steel lines on the frame. They seemed good as well. Then at the pump... return like looked good. SUCTION line did not. Extremely soft, tight radius bend so it was sorta flattened. Got the truck started and looked at the fuel pump suction hose again... it was pulsing like an artery. Seriously, it looked like a vein about to burst and was definitely going flat as the pump sucked. When we got the truck home, I replaced this hose with FI line with a longer radius bend. No more flattening, no more sucking closed. I intend to get to all the others to replace soon.

But I was still able to bog the truck out on long grades.

Other stuff I did while waiting on the filter to show up...

Replaced the divorced choke. The axle that the spring is wound on was spinning freely and not allowing the choke to operate correctly. Thought this could contribute if the vacuum in the carb pulled the choke valve closed. Replaced. Still able to bog it on long grades.

Checked fuel flow. Seems good. Have not checked pressure. I'm trying to get to that today.

No pressure or vacuum in the fuel tank.

While waiting on the CORRECT filter to come in, I did an ignition tuneup. Cap, rotor, coil, wires, plugs. Did not do module. Weights and springs looked fine. Still able to make it bog.

Also set the timing... but with a vacuum gauge. I have a light, and the balancer is marked for TDC... but the timing tab isn't. Don't have a piston stop or help to verify TDC so used my vacuum gauge. The truck would ping pretty good on 89 octane or less, so I set timing for max manifold vacuum (20"HG), less 1". Pinging went away, but seem to have lost a little pep. Will definitely establish TDC and time it with a light.

The fuel filter finally came in. The short one. But... without a check valve. Put it in two days ago. Since then have not been able to make it bog on a hill. But I'm still concerned that I missed something. Nervous about it coming back. I'm sure you guys know what I mean. Did I really get it?

Only things left on my immediate list are the PCV valve (but that seems to be working fine...) and the fuel pump itself. I've had electric pumps fail, but no experience with symptoms on a mechanical pump going out. Is it a gradual death or POW, yer dead! Will a pressure check help diagnose? rpmerf - you mention failing fuel pumps are worse when hot. Is that for mechanical pumps?

I'm hoping I don't need to drop the tank. It's a 40 gallon and just about full!

Appreciate the responses.

R