Ok took the mav on the road today to get gas...When I accelerated at normal pace no problem comes up to speed and shifts smooth as butter..While traveling at around 45 if I try and pass someone and get into the gas it hesitates and starts to sputter like it is getting choked out with fuel. this only happens when the motor is under load. In park the motor rev's up smooth and hold's a high rpm fine..Does this sound like a vaccum issue or a burnt plug. I have heard all kinds of responses locally...now my kick down cable is disconnected and I need to replace the stud on the carb I do not think that this would be affecting the motor.I have a msd ignition with msd dist. and 8mm wires could it be an electrical problem???this is a 302 with 600 holley carb. I did not have time to start diagnosing it today,hoping for the weekend....
only under load... I am going to bet that it is the fuel filter.... Had a 68 galaxy that did this very same thing once a month or so, It has sat before I bought it and the gas in the bottom of the tank was trash and would clog the fuel filter up and it would drive fine for a month or so then once the fuel filter got clogged it would go a couple miles then as soon as it warmed up (and sometimes before it would warm up) if I got into the gas to pull out in traffic especially on a hill it would spit and sputter and acted like it was getting flooded up. Then it got worse and started backfiring, I replaced a bunch of stuff, points, plugs, coil, adjusted the timing, and after all that it turned out to be the dang fuel filter was stopped up.
that will get changed first could use a new one anyway..Thaks for the quick responce.. I am glad I found this site the information is priceless...
Your float bowls may need a good flushing as well(new filter). Most auto part stores sell the gaskets seperately
Somebody butchered the filler tube on my 76 F100 so they could put leaded fuel in it. They got a little carried away and punctured the tube inside the fender such that it could pick up a little sand in the tank. The sand would clog the fuel filter about twice a year and cause the truck to behave just as you described. For a while I just kept an extra filter in the tool box, until my nonmechanical wife got stuck out in the middle of nowhere with it and two babies. Needless to say, I dropped the tank, cleaned it out and patched the hole right after that.
