I have a 87 3.9 holley 6280 carbed motor. (factory) Anyways, for awhile now, it seems to be running out of fuel. I can take off, wind it up in first gear, shift to second, and about 3/4 way through second, it will start missing like it is running out of fuel. I can let off the throttle for a few seconds and then it will run ok provided I don't go full throttle, and if I do go full throttle, shortly it will start cutting out again. Also, if in 5th gear at 55mph or so, if I go full throttle it will be ok for a few seconds, then I have to let off, because it seems to be running out of fuel. Again, let off for a few seconds, go back to cruising and its ok.


Now, for a little history on the truck. It has 76,000 miles. At about 64,000 miles, 4 years ago, I replaced, cap, rotor, plugs, wires, egr valve, rebuilt the carb. fuel filter, air filter, etc.


I figured that my problem was the fuel pump and since I plan to eventually put a carbed magnum 5.2 or 5.9 in it, I installed a carter p4070 external fuel pump. It is low pressure, 6psi. So I ran a new fuel line from the tank to the pump, and then to the carb direct. The pump does not require a regulator. I also ran 3/8 fuel line except for about 4in. at the tank and carb, where I had to convert to 5/16 for the fittings.


I installed a 3/8 fuel filter inline before the pump and I blew back through the fuel line into the tank to assure it was not stopped up at the strainer. It seems to be ok.


Also, I removed the needle and seat, seemed clean. So I put it back.


Any suggestions would be appreciated. My next step will probably be to take the carb apart, and check the float.


This truck has the computer controlled carb where it uses a o2 sensor for feedback. Oh, and the o2 sensor was replaced at the time I did all the other work.


Any suggestions are appreciated. Thanks