Lug/buffeting/hesitation???

[DynaBro]

Just cruising at like 50mph I always experience this sort of hesitation over and over. It is not on any specific cycle or timing. The best way I can describe it is like being in a boat against the waves. The motor never stalls or sputters or anything, revs fine, but is not accelerating smoothly. I thought it might be a fuel starvation issue so I ran my lines direct from the feed to the pump and from the pump to the carb and this did not solve the issue (but I feel like it sort of improved it?). Before that I was/am running a vapor separator with a return line (Yes I realize this setup was for 440/HEMI cars. The car came to me this way, with a crappy fuel filter rather than the VS, so I got a nice one and cleaned all that up with new rubber. The weird thing is they pinched off the return nipple of at the sending unit and ran the return line into one of the vents instead, which would cause pressure buildup and fuel weeping from the vent/hose junction at the tank. So to prevent the weeping that came out from those vent nipples (pushing through the hose junction) I decided to use a vented gas cap, which solved the fuel leakage issue. If any of that matters., which I do not think it does due to the direct line experiment I just ran not solving the lag.)

New plugs coming tomorrow just because.

Setup is a 383, nothing special. Brand new Edelbrock AVS2 650. 4 speed. MSD ignition.

Any ideas?

 

[493 Mike]

It sounds like a lean surge condition. Did you test for a vacuum leak? The metering rods may be too large in the cruise position/step. I'm certain others will chime in here.
Mike

 

[Bird 426]

Yes, sounds like it's a little lean. Can not help you tune that carb. The kits are almost $100.

 

[DynaBro]

Not timing?

I do get the occasional pop in the tail pipe when dropping out of gear at faster speeds. I thought that would indicate rich.

 

[Geoff 2]

It could be timing......& many other things. Try this simple test: engine idling & warmed up, close choke blade slowly until engine note changes. Wire the choke in this position & test drive. If problem is gone, carb is lean. Float level should be checked, should be 7/16".