The past few days ive had this issue. In the morning i go and let my truck warm up all the way and leave for school, it runs fine all the way out of my neighborhood but once i turn onto the road and try to accelerate, the rpms drop and it almost dies. It will die unless i throw it into neutral and hold the gas all the way in witch case the revs will climb very very slowly, it take around 15-20 seconds to climb all the way up. then it idles fine and if i hold it at 2000 rpm and put it in drive it will take off and run fine to school. The only other thing i notice when this happens is when the rmps drop the brake gets really stiff like i have no vacuum to the brake booster, when they finally climb back up the brakes return to normal. I cant figure why it only does it in the morning, but not after school or befor or after work even though the temperature is the same, 30-40 degrees morning and night. If anyone has some input or any ideas please let me know,
Thanks.

 

Hey there. It's possible that as it warms up your needle-n-seat are sticking in the open position and letting the carburetor flood the engine with gas. That's the only thing I can think of quickly that would require you to push the throttle wide open to get it to clear up.
But why it does it momentarily then stops is a mystery. Unless again, it's just the cold weather?
Where are you by the way? If in FL then I guess the cold is not the problem. Unless it's a gas mix thing? Running ethanol?

The choke plate opening up and leaning out the mixture (after warming up is the symptom and clue here) could cause it to stumble and even die, but you'd have to have practically lost all gas to get it to flame out so severely.

A bad/clogged fuel filter perhaps? Very common, but not as likely in your case since it would not usually change with temperature. But it would change with speed... Maybe at idle even with the choke closed it's not using enough fuel to empty the bowl, but once you start driving it a clogged filter would starve the carb for fuel.
Is the truck new to you? Or have you had it a long time? A few months after I bought mine it had the classic filter symptoms. Fine at slow speeds and around town, but on a slight uphill on the freeway it would bog down. Then it got incrementally worse until I just knew it had to be fuel starvation and a clogging filter.
Turns out the PO had installed two additional filters that I had not seen! Man were those suckers in awkward locations! Hated that old PO for a couple of hours while I removed them. Nice old guy though, so I could not hold it against him for long.

Anyway, a couple of possibilities.
Good luck.

Paul

 

I once had a similar problem, ran perfect at idel and slow speeds, tried to accelerate and it was a no go. Turns out a previous owner
replaced part of the metal fuel line with rubber and it was collapsing from the suction of the stock fuel pump