My truck had the same problem after it sat for a longggg time. I replaced fuel pump, line all the way back to tank (steel & rubber), sock in tank was clean. Then finally, I pulled the carb apart and found the problem. If you have a stock 2bbl....Remove the top of your carb, Remove the float, Remove needle valve and seat, clean the junk out of the screen under the needle valve and seat, re-assemble and enjoy your truck!!! Wish I had remembered the screen under the needle & seat valve before I spent hours chasing the wrong problems, it was full of debris. I'm betting you have the same issue.
Mine would run good for about 20 miles then act like a vapor lock, then it finally got to where it would only idle and starve out as soon as you hit the gas.
Good luck!

 

Wow, yes it is a 2 barrel. I'll try it in the morning, thanks for the help.. I'll post here with what I find out.
Mark

 

Count me in as well. Just too much like my own problems with mine right now. HATE DROPPING TANKS BUT YOU GOTTA DO WHAT YOU GOTTA DO. I have seen the fuel strainers collapse when they get too dry too. Pull the strainers and see.

 

Can't be the tanks as it did it with the gas can under the fuel pump.

 

Unless you find the fuel inlet clogged as suggested by redsuperduty (and that is a real possibility) you have eliminated everything in the fuel system.
I think that you are paying too much attention to how the fuel "looks" going through the filter and this is keeping you from considering the possibility of a problem somewhere else.
Diagnosing something like this from xx miles away, not seeing, hearing, or being there is a crapshoot at best.
From my experience, once you check the fuel inlet clogging, and can eliminate that you need to check other areas for problems.
Many, many times I've seen people do exactly what you're doing (and I've done it myself quite a few times): chasing a fuel problem when its actually an ignition problem and visa-versa. These two separate systems can have the same symptons when there is a problem.
I'm just saying don't get tunnel vision.
Good luck. I know you'll find the problem.

 

mike 0o0o0o ha s good point the ign mod takin a dump can give a similar concern. what kind of clear fuel filter? a glass one with ends that thread on? if so sometimes the o-ring dont seal right and it will allow you to suck air into the line(had that before and 86'd it), if its a plastic one what condition is it in? might help to replace it if it is questionable in apperance..

 

Something you might do is take it for a drive and when it craps out on you pop the hood and check for spark. If you have no spark then you know it's the module crapping out after it gets hot. Might have a friend follow you so they can lend a hand.

 

It was/is the glass filter. I looked at the O rings/seals and replaced yesterday. I have the fuel pressure gauge in line just before it.
Troubleshooting steps are as follows:
Step 1: Is to take the carb off and look inside at the little screen that redsuperduty suggested. (Today it was 97 with a heat index of 107, Dallas in the summer, argh).
Step 2: I had bought a 4 barrel carb/intake setup so If that doesn't do the trick I also bought one of those 4 barrel to 2 barrel adapter plates, to put the carb onto the stock intake. Since I had already had the carb intake in route that is.
Step 3: Is to swap the DS 2 as Mike suggested. (If I had this I would of tried it first, as Mike is pretty dead on with his suggestions)

 

What are you talking about Dude?! Today felt fantastic outside, compared to the last few weeks anyways haha. Where in Dallas are you? I live over by White Rock Lake, Old Lake Highland area.

 

Only if your comparing the temp to Hell would it of been cooler and not by much!!!
I live in Highland Village off of FM407/Justin Rd next to Lake Lewisville

 

UPDATE:
I also had tried an external gas can straight to the fuel filter. I also swapped my 2 barrel carb with a 4 barrel using an adapter plate ($17.00) sold by ORielly's. I installed a fuel pressure guage right before my clear glass filter which went right into the carb. With the truck idling for hour 45 mins. with the A/C on the temp guage between 1/2 and 3/4. Mine would sit there idling for 30-45 mins then I would see the fuel guage drop to 4 1/2 pounds of pressure start flopping the gauge. While looking in the sight glass I could see the gas almost gone and then bubbling then filling the filter back up. Then doing it again. I took off the intake and swapped it with a Preformer 400 and removed all the vacuum lines and EGR except for the 2 lines to the distributor from the intake and carb. While apart I found the water jackets from the heads to the intake closed with rust buildup. I cleaned them out installed the new intake, carb and also the DS2 module. I then saw that my gas line from the fuel pump was resting against the front of the block. I thought great its vapor locking. I moved it away and same thing. I did see that the line coming out of the fuel pump appears to be cocked just a bit (maybe crossthreaded?) and only threaded on a couple of turns. So I'm going to swap in the fuel pump again (this time with a Holley) and try it out also bypassing the aluminum line between the fuel pump and carb. by running an external line rubber hose to the carb (leaving the fuel filter and fuel pressure gauge still in line)around all the heat from the front of the engine.

Quick recap of things done:
replaced fuel pump
replaced carb
tried both tanks individually bypassing the fuel switch
tried extrenal gas can right under fuel pump
tried new DS2 ignitian module
removed all vacuum line but distributor lines
cleared blocked water passages to inake from heads
replaced intake manifold
moved aluminum fuel line from against block