One thing I have noticed for about the past year is if it was raining or had been raining and the first time I would start it I would run ruff and maybe want to stall if I took my foot off the gas, but once it warmed up it was ok.
That made me think it needed a new set of plug wires.
I started it up at night and didn't notice any of the wires arcing.

It got worse the other day when I made my first post & it was real foggy that morning and today it was sunny & in the 50s & started right up, idled smooth but still hesitates & pops thru the carb if I accelerate quickly.

I'm tempted to buy new wires,cap & rotor & a coil & pray that fixes it.

 

That sounds to me like moisture getting into the distributor. Try a tune up... if you have not done one in awhile.

 

I just changed the plugs, wires, cap & rotor.

Then I went to change the pcv valve & the old valve broke trying to remove it & part of it fell down into the valve cover so I had to remove the grommet & it was so brittle that it broke.

I went to 6 auto parts stores & the 3 that had it all were the wrong part which was the grommet for the oil breather on the other valve cover.
I found one online & it won't be here until probably next Tuesday so I'll have to wait to see if all that fixes the problem.

 

i have a 87 with a 3.9L 6, with a holley 6280 2bbl Carb and mine had the same issue and the choke was all messed up. im not sure what to do about fuel injection, but thats what my problem was

 

I finally got the pvc grommet & installed & as I expected there was no change in the symptoms & it still hesitates & pops thru the carb under load & in neutral if I quickly push the pedal to the floor.

I also performed this test with the pvc hose disconnected & hose & port plugged with the vac/pressure gauge connected to the oil breather hose that had been disconnected from the air cleaner.

Start the warmed engine and observe the vacuum gauge.

Allow the engine to idle for approximately 30 seconds. Do not allow more than 3psi (20.7 kPa) of pressure to develop in the engine crankcase.

If the attached vacuum I pressure gauge does not indicate that a vacuum is present in the engine crankcase, then the intake manifold plenum pan gasket is good and no further internal engine vacuum leak diagnosis is required.

If an internal vacuum leak is present then perform the Repair Procedure.

There was about 1.5 lbs of pressure when performing the test so I guess that means the plenum gasket is good.

I'm open to suggestions on what to try next.

 

I tested the map sensor & the throttle position & both check out ok but now I don't have any fuel at the valve on the fuel rail.
It's looking like the fuel pump died.
If I spray carb cleaner down the throttle body It will run for about 5 or 10 seconds and quit.
I checked the relay and it is working so then I went back by the fuel tank wiring harness along the frame rail next to the tank and found the dark green/black stripe wire and probed it with my voltage meter & I'm getting battery voltage when the key is turned on & it quickly goes down to about .04 volts then if I cycle the key on I get the same results.
What puzzles me is that I'm not getting a constant 12 volts.
I can't hear the fuel pump come on & I don't have any fuel at the fuel rail.
I would think that if the pump came on and built up pressure then the voltage would drop to shut the pump off after pressure built up, but I have no pressure.
I don't want to spend $150 for a pump if that's not what's causing the problem.
Does any one know if I'm getting the correct voltage results?

 

I finally got a new pump & installed it & all is well now.
Runs like a charm.

Thanks to all that helped.