Stuttering inline 6

[matt_l]

I drove my truck up to the glass shop yesterday to get a new windshield put in, and at about 40 mph the motor would start to miss/stutter. If I slowed down, it would run fine, and then as soon as I got over 40 or so, it would start to miss again. It seemed worse on the up hills, but hard to tell. What should I check? I ran ok when I drove it home last year. Ok, not great then either, but it did not have this problem.

[hotrod66]

check distributor hold down had that happen to me. also check fuel filter and under distributor cap just to make sure that its still all together (also had happen to me). hope you figure it out bud, hate when my truck isn't running right makes me feel like im not running right to.

[Dillon Rock]

Yeah for me it's normally the fuel filter that is the culprit. But in that case it will stutter then die of starvation so I just pop off the filter and chunk it out in the curbside to get the rust out, put it back in and go. Lol. Also check your stone filter in the carb at the fuel inlet connection. It should be a 1 inch wrench to get the cover off and has a spring and plastic gasket to seal it so be sure not to loose either. Best of luck to ya pal.

[tincan1966]

If you've only driven it twice in a year there's a chance you could have some fuel getting stale or have condensation in it. Also, any sediment you might have in the carb, is surely going to settle out in the bottom, too. Doesn't take much on the 1bbl carb to cause some blockage.
It is also possible that the advance in the distributor is a bit sticky from sitting, also.

Need a little more info about your setup to be much help. Real hard to diagnose problem thru a forum anyway.

Not trying to promote any certain products, but I've had good luck using the Lucas fuel treatment in customer's vehicles that don't get driven often.

[PGSigns]

If it has not been driven since some time last year and now it is not running that well I would look right to the fuel. Best solution is to drain the old out and go with some new fuel. If the truck is not going to get driven much in the near future I would put rec fuel in it. The stuff with no ethanol and ad some stabilizer.
Jimmy

[matt_l]

Thanks for the feedback guys. One more question, does anyone know where I can find the vacuum hose diagram?

[Dillon Rock]

Yeah vac lines is important to the distributor. Make sure there is no loose connection on it. Vac diagram is simple should be one from the bottom of the carb to the distributor and one from your pcv valve to the plenum on the intake.

[matt_l]

After a new fuel pump, all new fuel lines, spark plugs and wires, and inline fuel filter, I tracked the issue to a plugged filter inside the inlet to the carb. I didn't even know there was a filter there. Learned something new, so it is a good day!