Starving for Gas and getting worse!

[64shortbox]

As franken said, check for fuel delivery. Not just pressure but volume. Get a 1 or 2 gallon gas can with gas, set it on the ground - it should fit between the radiator and the motor under the lower radiator hose. Get some gas hose and run it from the suction side of the fuel pump into your gas can - this will eliminate your fuel line fuel tank pick up etc. from the loop. Will the truck start? If not prime your carb and try starting again. Does the truck start now? If so, does revving it a little in neutral cause a fuel starvation problem? If so it can only mean one problem you have a bad fuel pump. Since you've replaced the fuel pump twice - we're back to the eccentric on the camshaft being worn - that's providing the fuel filter in the Q-Jet carb isn't in backwards and the spring in it is OK. You can also buy a fuel pressure gauge from Harbor Freight for $15.00 - but it's not just fuel pressure but fuel volume. https://www.harborfreight.com/fuel-p...pressure+gauge Dang, I just left the Ahwatukee area of Phoenix and am now home in edited by staff - I would have been more than happy to come over and help you trouble shoot & repair your fuel problem. I'm retired, so every day is a Saturday & I have nothing to do and all day to do it in.

[Fleeting65]

***UPDATE***UPDATE***UPDATE***UPDATE***UPDATE***

To all those who suspected it was the coil, you seem to be ahead of the crowd...

Master mechanic came over to the house last night-- checked the fuel delivery system, including pump, finding no issues whatsoever. Carb & choke was good, too. Carb was correct for the manifold (no hot slot). He approved of the (like-new) plugs being put to the wire wheel for a good cleaning. He then plugged his spark reader into #1 cylinder and we took the truck for a ride...

It only took 3 minutes for him to experience that dreaded bogging and choking sensation. He saw that the spark indicator was reading quite a weak spark, so we limped it home, took the distributor apart, and this is what we found: a ground strap that was rusty and an original (1976) coil that had seen better decades.

For the price of a new coil, rotor, cap, etc., it made sense to replace it all. We'll be installing an MSD Street Fire. The mechanic was confident this was the issue. Still, as a guaranty, he said, "If this isn't the cause, then I'll buy the MSD back from you 100%."

I'll keep you all apprised on its results.

[JPBrecheisen]

If it's not with the ignition, I'll recommend the float level in the carb be checked. Especially since it's been apart.

Had one that wasn't set right (was too low and not keeping enough fuel in the bowl) and it would go traffic light to traffic light just fine but would run out of fuel after a long acceleration on a climb or wound up at highway speed for about 2 minutes or less.

If you're not resolved yet, recommend that be checked like others have already mentioned.

[Fleeting65]

*******PROBLEM SOLVED*******FINAL UPDATE*******

I am embarrassed. I am humbled. But I learned the value of a true fellow car fanatic mechanic vs some shop mechanic. I realize I'm now exposing myself to a fair amount of flack and "told you so", but I believe in full transparency.

Turns out the cause of the bogging wasn't that old distributor, and it wasn't the carburetor or any of its inner components. The source of the bogging was a hidden SECOND (in-line) fuel filter tucked within the frame's front horn...and...AND...that inline filter was REVERSED! Yes! It was facing the wrong direction! It was discovered as soon as he heard it sucking for fuel when we took it for another ride at night. While I do not know just who installed that filter (not me) -- maybe the non-English speaking person who sold me the truck in 2014. That would make sense if he couldn't read English.

Still, my previous mechanic DID change the mechanical fuel pump recently. So he had to see it when he hooked up the hose off that 2nd filter. Because of how it was tucked away, I didn't even see that it existed, otherwise I would've turned it around so that it was properly facing the correct direction "---> TO CARB".

And ohhh, it was a mess inside! Years of grit, dirt and impurities going straight into the paper filter the wrong way! Yikes! We were stunned, laughing that the truck even ran as long as it did!

But the silver lining is that its brand new MSD Street Fire distributor that was just installed was a No Charge from this mechanic who kept his earlier promise. We still need to install a timing tab and dial it in (it runs jittery at low speeds), but I had it up to 80mph a few times already.

Thank you all again. I thought I had just 1 filter in the carb's inlet. I never knew I had another inline filter, let alone one facing the wrong direction! Like I said, I'm ashamed.

[cwcarpenter98]

No need to be ashamed, an additional filter like that was not stock, so no way to know it was there until you actually lay eyes on it. I just fought what I thought was a timing issue on my 81 that was actually just me not putting enough gas in the tank for the truck to run effectively

Glad you got it figured out and can get started on enjoying your ride!

[Braunschweiger]

Found bugs and the truck runs,
a hidden and twisted fuel filter is also insidious.