Engine running ruff under 1500rpms

[6768chevylover]

The other day my carb sprung a leak on my truck. I thought it was the bolt at the bottom right above the acc. pump. Its a holley 700 dp.. ended up finding out it was the acc. pump gasket. In the mix of me figuring this out I was driving my truck with a leak til I got it figured out but then my truck started running ruff at idle and during acceleration til passed 1500 rpms but even after 1500rpms I would feel hesitations(bucking) every so often. Then I fixed the gasket thinking it would go away. didn't happen. Thought maybe it would need a tune up. Gave her new plugs and wires and cap and rotor. feels like it runs a lot better but it still has hesitation and bucks. Could this be a fuel pump issue? Has an eddy fuel pump. Its been on the truck for about 10 years now. Trucks only been on the road for about 7 years. Anything else that could cause this problem or look for? Thanks, Mike

[garyd1961]

Not saying this is your problem but my old motor with a worn out cam wouldn't run worth a crap at low speeds, especially at idle.

[truckster]

I would start by looking for a vacuum leak. Slowly spray carb cleaner around the base of the carburetor, where the intake runners go into the head, and any vacuum ports on the carb or intake. If the RPMs pick up when you hit a particular spot, you've identified the area of your leak.

Some guys use a propane torch to do the same thing. Just make sure the torch isn't lit.