I'm still troubleshooting a stumbling problem that I've had these past few weeks since I bought the truck. It'll nearly die if I stab the gas too fast and it doesn't really have the power I feel a 460 should. Part of that is probably due to the Moto-Holley it came with but I have some trouble believing a stock carb could be THAT bad (it's actually a rebuilt carb, though I have no idea when it was put on). It's getting replaced in the near future and I'm gonna replace the fuel filter this week sometime. I'm not sure how likely it is that there's crap in the lines themselves, seeing as how the truck has a plastic tank..well the main one is anyway. But I figured Seafoam running in there couldn't hurt. I know the last owner seldom used the truck, it mostly sat on his achorage. Maybe I'm just thinking out loud...but anyway opinions are welcome.

 

Seafoam isn't that expensive and it works real well. But there are always things that only a tear down of the fuel system will cure. Try it, as it won't hurt anything. I'd check the accelerator pump and linkage if I were you. Go here for info;

http://www.holley.com/TechService/

I also have a thing for major league fuel/water separator filters too. NAPA Pn# BK 7511145 , $26.99. Since I started using these I have not had a dirty carburetor problem one.

 

Double check the squiters in the carb. If you stab the gas and it stumbles, could be that it's not getting enough gas.

 

I am not sure that looking at the squirters is going to tell you anything unless you have done a lot of carb work. The only thing you can confirm is if there is gas there and in both barrels. If there isn't then you definitely have pump problems, if you do then you don't have enough pump throw. That 460 takes a large shot of gas to get it going without stumbling. And yes that stock carb can be a problem depending on who rebuilt it.

I would check the pump arm and make sure it is set for maximum throw. There is usually only two things that cause a stumble. That is the pump throw and a carb that is set to lean.

You would have problems at higher rpm's not at idle, if you had a blockage such as a plugged filter or crap in the lines.

 

sounds like the accelorator pump has gone bad