Straight 6 random power loss?

[Joe Z]

I've had the truck and issues here and there for about 6 years now and recently started having some odd power loss. It's a short bed 2wd 250ci truck with the Muncie 4 speed. It's a rolling rebuild with all new plugs, wires, carb rebuild, the whole works. but after having a new factory style exhaust installed I started to notice a slight power loss here and there I thought was just from not running open pipes. Now at random it losses all power and the farther I press the peddle the closer it comes to stalling. But if I let off it slowly climbs back to idle and stays there til' I try and accelerate again. But it doesn't just do it when hot or cold and it doesn't always do it for a long period of time. Is it possible the exhaust is clogged or the cat is bad or am I missing something? Thanks.

[Oberon67]

Are you running the original Rochester Varajet 2-barrel carb? It sounds like you may have lost your accelerator pump.

[Joe Z]

Yeah but it was rebuilt last year. How would I check for that?

[Oberon67]

Uncertain. I'm sure someone else here can tell you.

[Joe Z]

Thanks for giving me a place to start. I'm going to unhook the exhaust and see if it still does it while straight piped and if so I have an extra carb that I can put on to check if the the problem remains or not.

[D13]

Also ignition. Sudden change in ignition timing caused by bad ESC system (if ex-California car) or worn distributor shaft bushings. Check for excessive pllay in the shaft or a lot of damage / carbon tracking in the cap.

[Joe Z]

Everything is new in the distributor. I redid the entire ignition system over the winter last year so it shouldn't be that. I haven't touched the timing yet because I planned on having the motor professionally rebuilt this year.

[cheap]

if you give it gas and it falls on it's face, a culprit could be a bad accelerator pump, like it's a little light. I rebuilt a carb on my 250 and still had the same problem, so i switched to a different one and it cleared up. Not sure if that's the issue, other may provide more help

[Joe Z]

Between work and weather I just got to work on the truck over the weekend. Apparently buying a fuel pump four years ago (according to the receipt) and not realizing it was never put on can have negative consequences. Seems to have been the problem but a good work out will tell. Thanks for the advice though, never know when it'll be needed.