[664ever]

have a 66 chevelle with a 350 while in gear car bucks badly step on gas and bucking stops carb is a holley street avenger have changed in line filters readjusted floats and tuned up any ideas on what could be making car buck thanks for your help

 

[Tom Mobley]

you mean like on the highway? around town? do you know what the RPM is while it's doing this?

 

[664ever]

on the highway steady 65 car bucks around town third gear fourth gear at 40 mph

 

[Tom Mobley]

does the engine have a big cam in it?

what's the rear end gear ratio?

 

[Tom Mobley]

Steve, I got your PM, but please post the info here. PM doesn't work so hot since only 2 people can see it.

 

[664ever]

carb has a lot of carbon residue cleaned that also might have got a tank of bad gas
put 2 bottles of dry gas ran it for twenty miles still has a little bucking

 

[eric13617]

When is the last time you checked the needle and seat? Front and rear. A piece of trash in there and the engine will flood itself to death.
Did you clean the idle air bleeds when you did a tune up?
When you are cruzing you are probably still on the idle circuit, and for the most part a Holley is set rich, in my opinion.

Carbon residue in the carb is a clear sign of Reversion.
A tank of bad gas could make it miss, but I wouldn't think it would surge.
When is the last time you checked you timing and where is it set at. Initial and total.
Can you post some specs., please?

 

[Keith Tedford]

If the carb is jetted down too far you can get lean surge at highway speeds.