hesitation and almost stalling
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Joined: Jan 2000
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From: Virginia Beach
hesitation and almost stalling
78 F-150, 351M, C-6, stock 2-v intake and stock motorcraft carb.
Carb rebuilt about 6 years ago by Pony Carbs.
Starts fine cold or warm.
Idle's fine sitting still.
Approaching a stop and let off the gas, the engine almost dies (rpm less than idle, no tach to measure exact amount) and then goes back to idle.
Sometimes it will not go above 25-40 mph. On the gas to accelerate, it hesitates and starts to almost stall somewhere in that speed band, sometimes 25, sometimes 40 mph. I say almost stall, but its more like its not getting enough air, like the choke isn't working. I pull over, put it in neutral or park and it revs up just fine. I try again to get it going, and it does the same thing. Next day it will drive just fine.
My gut feeling is the choke for the hesitation or maybe the accelerator pump, but not sure why it would try to stall letting off the gas coming to a stop. But as with anything, confused as to why it works fine one day and then acts up the next.
Carb rebuilt about 6 years ago by Pony Carbs.
Starts fine cold or warm.
Idle's fine sitting still.
Approaching a stop and let off the gas, the engine almost dies (rpm less than idle, no tach to measure exact amount) and then goes back to idle.
Sometimes it will not go above 25-40 mph. On the gas to accelerate, it hesitates and starts to almost stall somewhere in that speed band, sometimes 25, sometimes 40 mph. I say almost stall, but its more like its not getting enough air, like the choke isn't working. I pull over, put it in neutral or park and it revs up just fine. I try again to get it going, and it does the same thing. Next day it will drive just fine.
My gut feeling is the choke for the hesitation or maybe the accelerator pump, but not sure why it would try to stall letting off the gas coming to a stop. But as with anything, confused as to why it works fine one day and then acts up the next.
Hotshot
Joined: Oct 2002
Posts: 18,488
Likes: 22
From: The Big, Oregon
More like the advance weights are sticking. I meant the mechanical timing advance. You can check them by popping off the cap, and turning the rotor by hand a little. If the rotor springs back quick, the system works fine. If the rotor comes back slow, that's the problem.
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